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3636 North Central Avenue STE 800 Phoenix, AZ 85012
602-265-5200
cosmas@cosmasonyia.com
  • Practice Areas
    • Divorce
    • Legal Separation
    • Child Custody
    • Phoenix Child Support
    • Spousal Support/ Alimony
    • Order of Protection
    • Arizona Paternity/ Maternity
    • Grandparents’ Rights
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Family Law Firm in Phoenix

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Divorce
Child Relocation Out Of State
Property & Asset Division
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Client Reviews

We have multiple Five Star Reviews from happy clients on Google

Mr. Onyia is a magnificent lawyer, and I highly recommend him to anyone looking for a dedicated and passionate lawyer. He is eloquent in his delivery, as well as direct and efficient. As a client, I felt prepared and looped in at all times, without needing to chase him for an update. If you’re looking for a lawyer who will give you 110%, look no further, he’s the one.

– Deeb H.

Mr. Onyia is an outstanding lawyer! He explained and help walk us through every step. We had lots and lots of questions and he took the time to answer them all either in person, on the phone, or through email. Would highly recommended him. He’s straightforward and reasonably priced. I’m very grateful I found Mr. Onyia.

– Miguel A.

I want to take a moment and recognize this Awesome Lawyer Cosmas Oniya; that took care of my case and blew the other parties lawyer out of the water! Very qualified and has been in the business for over 20 years! I definitely recommend this law firm and have already referred him to family and he also won their case too! I fell as if he went above and beyond for my case and got every wrong thing done to my daughter and I right. He was reasonable with my retainer and allowed me to pay him in time before court. I wouldn’t go any where else for my case needs. Thank you 😊

– Annamarie B.

This attorney is AMAZING!!! His fees were very reasonable. He doesn't try to nickel and dime his services. He returns phone calls in a timely manner. He's a brilliant family law attorney who is also humble. I received GREAT results hiring him. My only disappointment is that I didn't find him years ago. I would definitely recommend Cosmas for any and all family court issues.

– Kama G.

Cosmas is the most genuine, caring and committed attorney we know. His understanding of the law is reflected in his work and his ability to convey that to his clients is appreciated. He communicates effectively and no matter the day he is always available.

– Renee E.

Great lawyer who was very informed and direct. I never felt confused about any step in the process, as he kept us updated and explained everything thoroughly. I highly recommend him if you're looking for a lawyer that truly cares. 10/10

– Rana A.

Great lawyer, attentive to detail, and very thorough. I was kept up to date on everything, and felt very prepared. He knew the case inside and out, and was very efficient. Highly recommend, and will definitely be my go-to lawyer.

– Osama

'The Best' Mr. Onyia walked me through the whole process of family court, great communicator and affordable fees no hidden cost explained everything up front! Thank you Cosmas for a job well done!

– Roberta G.

Very great attorney highly recommend him. He is extremely friendly knowledgeable and helpful and on time with his appointments when they here with my sister for divorce litigation and I’m very glad we did and highly recommend him to you.

– Kelly G.

Had the pleasure to speak to Mr Onyia today and it was above and beyond what I expected, I ended up learning alot and gave me all the knowledge I needed and more, hence gave me confidence in regards to my case. Very much recommended! Thank you sir.

– Mahmoud A.

Mr. Onyia was nothing shy of perfect with his brilliant focus and representation. I would highly recommend him to anyone.

– Rick L.

Mr. Onyia is always available and dedicated to his clients. His expertise far exceeds that of his peers.

– Arthur A.

Cosmas has shown his clients the dedication and tremendous service that they deserve from a Phoenix family law attorney.

– Tempe

Phoenix divorce attorney with tremendous knowledge and experience. One of Arizona's very best in my opinion.

– Brian G.

Amazing Attorney! He helped my uncle and bf. Anytime I can I refer people to him.

– Juanita C.

Family law attorney, Phoenix AZ

FAMILY LAW ATTORNEY IN
PHOENIX

Family law matters can reshape nearly every part of your life, including your finances, your parental rights, and your future stability. While Arizona’s family law system provides clear legal resolutions, getting there requires legal guidance and thorough preparation.

The Law Office of Cosmas Onyia boasts nearly 30 years of focused experience in Family Law. We have garnered a reputation in Phoenix for providing comprehensive legal counsel tailored to the unique circumstances of each client. If you are managing a serious challenge with your family, it is time to work with a Phoenix, AZ family lawyer for professional legal representation.

Why Choose the Law Office of Cosmas Onyia?

Family law matters are deeply emotional and confidential. This requires choosing a lawyer who is trusted and can handle sensitive issues with both strategy and discretion. Family cases require more than court filings and procedural steps. They demand a skilled family law attorney who can respond to your concerns, anticipate legal obstacles, and guide you toward outcomes that are fair, enforceable, and sustainable.

Here’s what makes us fit for your family law representation:

Many Years of Focused Experience: Since 1996, Attorney Cosmas Onyia has practiced family law exclusively. This gives clients the benefit of legal insight honed through thousands of family law cases across Arizona.

Client-Centered Legal Strategy: Every family situation is different. The firm does not apply formulaic solutions. Instead, it works with each client to develop a tailored legal approach that reflects their priorities, whether those include maintaining child stability, preserving financial stability, or ensuring long-term co-parenting viability.

When your family’s future is at stake, you deserve legal representation that is reliable, knowledgeable, and fully engaged. The Law Office of Cosmas Onyia will provide that level of advocacy to your case to ensure your outcome reflects your best interests.

Law Office Of Cosma Onyia
Practice Areas

Family law is a wide legal topic involving matters that directly impact the people and relationships that matter most. At the Law Office of Cosmas Onyia, we understand that various issues can arise at different stages of marriage, and therefore, we offer comprehensive legal support to help you manage challenging transitions with stability and foresight. Our family law services include:

Divorce and Legal Separation

Ending a marriage is never easy, and the legal process can quickly become overwhelming without guidance. Arizona allows for either contested or uncontested divorces, and each route requires thoughtful legal planning. We can help with the following:

Filing for a contested or uncontested divorce

Identifying and dividing marital assets and debts

Resolving child custody and support within the divorce proceeding

Drafting and negotiating settlement agreements

Some couples can opt for legal separation as an alternative to divorce, especially when there are personal, financial, or religious reasons to remain legally married. Although it doesn’t terminate the marriage, legal separation addresses many of the same legal issues as divorce.

Divorce

Child Custody

Custody disputes strike at the heart of a parent’s role and often become the most difficult part of family litigation. Arizona law calls for custody decisions that reflect the child’s best interests, but determining what that looks like requires advocacy grounded in the facts of your family life. This involves the following:

Legal decision-making (sole or joint)

Physical custody and parenting time

Emergency custody orders

Drafting and enforcing parenting plans

Custody

Spousal Support (Alimony)

Spousal maintenance is usually determined by law when one spouse lacks sufficient resources to meet their needs after divorce. Courts examine numerous factors to decide whether support is warranted and, if so, how much and for how long. We offer the following services:

Evaluating eligibility for temporary or long-term support

Calculating amounts based on need and earning capacity

Filing or contesting spousal support petitions

Addressing financial disclosures and lifestyle evidence

Our firm provides clear guidance to ensure that any support arrangement reflects both parties’ financial realities, whether you are requesting maintenance or opposing it.

Spousal

Grandparents Rights

While parents have primary legal standing, Arizona law does allow grandparents to request visitation and, in rare cases, custody under specific circumstances. Our services involve:

Evaluating eligibility based on divorce, death, or estrangement

Filing petitions for visitation under A.R.S. § 25-409

Gathering evidence that supports the child’s best interest

Seeking court recognition of long-standing caregiver relationships

These cases involve numerous legal considerations and are driven by specific facts. We provide clear advocacy for grandparents who play an active, beneficial role in the child’s life.

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Paternity and Maternity

Establishing legal parentage is a prerequisite to obtaining custody, parenting time, or child support. In Arizona, paternity can be ascertained voluntarily or through court-ordered testing and adjudication. We can help with the following:

Filing paternity actions in family court

Seeking or contesting legal recognition of parentage

Petitioning for custody or visitation following paternity confirmation

Whether you’re seeking to assert parental rights or defend against an unsupported claim, we ensure your case is presented with complete and accurate documentation.

Baby

Visitation Rights

Parenting time is vital to maintaining a child’s relationship with both parents. Arizona law encourages regular, meaningful visitation unless there’s a strong reason to restrict it. We can help with the following:

Creating detailed visitation schedules

Enforcing time-sharing arrangements through the court

Responding to denied or interrupted parenting time

Representing noncustodial parents in visitation disputes

When visitation disagreements arise, a Phoenix, AZ family law lawyer can help restore balance and promote arrangements that support the child’s emotional health and foster parental bonding.

Visitation

Child Support

A separation or divorce shouldn’t compromise a child’s financial well-being. Arizona uses a standardized formula to calculate child support, but accurate support orders require a full understanding of income, parenting time, and the child’s specific needs. We can help with the following issues:

Establishing initial support obligations

Reviewing income, benefits, and parenting time for accurate calculations

Accounting for health insurance, childcare, and educational expenses

Preparing and filing child support worksheets and financial affidavits

Support

Division of Property and Debts

In a divorce, property amassed during the marriage is presumed to be community property and must be divided equitably. Identifying what belongs to the marital estate and valuing those assets requires careful legal analysis and consideration.

Just as property must be divided, so must the debts incurred during the marriage. These include credit cards, car loans, mortgages, and other financial obligations. We assist with dividing assets and debts fairly to ensure that your financial rights are preserved through final judgment.

Division

Order of Protection

In cases of domestic violence, threats, or harassment, the court can issue orders of protection to prohibit contact and ensure personal safety. These orders are time-sensitive and can be contested by the accused party.

A family law lawyer in Phoenix, AZ can help in seeking or defending against restraining orders. Whether you are in danger or wrongly accused, we will act quickly to secure a legal solution that protects your safety and rights.

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Custody battle

About the Attorney

Cosmas Onyia, P.C. is a family law firm helping clients resolve their family law matters since 1996. Attorney Cosmas Onyia has over 25 years of experience representing clients and aggressively fighting for their rights inside and outside the courtroom. He profoundly understands family law and how it can impact his clients’ most private and sensitive issues. That is why Cosmas Onyia approaches each case with compassionate understanding.


Here at Cosmas Onyia, P.C., we believe that each client is unique; that's why we provide personalized solutions that'll tailor to your needs. Mr. Onyia takes the time to listen to your expectations and goals to determine the best plan of action in your case while working hard to defend your legal rights in negotiations and court.

Frequently Asked Questions

The duration of the finalization of the divorce varies from case to case. Arizona divorce proceedings have a 60-day cooling-off period, which starts when serving a divorce petition to the other spouse.

When a divorce petition is filed by one spouse and the parties don’t have disagreements on any issues, the court generally announces a decree after a cooling-off period. However, if you have a conflict with your spouse on crucial issues like child custody and division of assets, the finalization time increases. The duration will depend on the complexity of those issues.

You must have lived in Arizona for at least 90 days to file for divorce as per section 25-312(A)(1) of the Arizona Revised Statutes.

Arizona courts don't favor a parent based on gender when determining child custody. Arizona Revised Statute Section 403.02(B) states that the court shall not give preference to a proposed plan due to the gender of a parent.

The courts serve the best interests of the child. Therefore, they only consider factors that may benefit the child. Some of these factors include:

  • Level of the child's relationship with each parent
  • History of child abuse or domestic violence
  • Potential future relationship between the child and each parent

Arizona courts consider a child's wishes about their living arrangements if they are mature and of a suitable age. But, this is not the sole factor they consider when determining living arrangements. So, where your child will live depends on the facts of your case.

Arizona is a no-fault state; therefore, you don’t need specific grounds to file for divorce. You only need to state that your marriage is irretrievably broken, and there is no hope of reconciliation. You don’t need to prove the fault of your spouse to file for divorce.

However, if you have a covenant marriage, you must establish a specific ground for divorce. You must either both agree to divorce or prove in a court that the other spouse has committed one of the following acts:

  • Adultery
  • A serious crime resulting in imprisonment
  • They abandoned you for at least one year
  • Physical or sexual abuse
  • Domestic violence
  • Living separately for two years
  • Regularly use drugs or alcohol

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Why can’t I file for divorce on my own?

Whether you plan to file for a contested divorce or an uncontested divorce, the assistance of an experienced divorce attorney is advisable.


If your marriage has conflicts, you may not be able to negotiate your fair share due to your history with your spouse.


However, in an uncontested divorce, you may have difficulty dividing marital assets fairly and handling all the legal paperwork.

How long does a family law case take?

The duration of the finalization of the divorce varies from case to case. Arizona divorce proceedings have a 60-day cooling-off period, which starts when serving a divorce petition to the other spouse.


When a divorce petition is filed by one spouse and the parties don’t have disagreements on any issues, the court generally announces a decree after a cooling-off period. However, if you have a conflict with your spouse on crucial issues like child custody and division of assets, the finalization time increases. The duration will depend on the complexity of those issues.

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Family

Speak with a Phoenix Family Law Attorney Today

When managing family issues that affect your family, you can take legal action to protect your future. At the Law Office of Cosmas Onyia, you will receive representation grounded in Arizona family law and tailored to the details of your situation. As part of our practice, we will take the time to understand your concerns so that we can provide informed guidance. Call us at (602) 265-5200 to discuss your situation in confidence.

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Filing for Divorce


Filing for a divorce in Phoenix, can be a complicated matter, especially if there are assets, property and parenting time that are to be divided between the couple filing divorce in Arizona. As an experienced Phoenix divorce lawyer our job is to provide expert advice, and work diligently to protect your interests.

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Child Custody


Child custody cases can be emotional for both parties involved. Different types of child custody exist in Arizona. Our Phoenix child custody lawyer has handled many cases resulting in favorable outcomes.

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About The Attorney


Cosmas Onyia, P.C. is a family law firm helping clients resolve their family law matters since 1996. Attorney Cosmas Onyia has over 25 years of experience representing clients and aggressively fighting for their rights inside and outside the courtroom. He profoundly understands family law and how it can impact your well-being.

Here at Cosmas Onyia, P.C., we believe that each client is unique; that's why we provide personalized solutions that are tailored to your needs. Mr. Onyia takes the time to listen to your expectations and goals to determine the best plan of action in your case while working hard to defend your legal rights in negotiations and court.

Phoenix Divorce Attorney
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Couple arguing in front of the child

PHOENIX FAMILY LAW & DIVORCE ATTORNEY COSMAS ONYIA | Divorce Attorney Phoenix

Address : 3636 N Central Ave STE 800, Phoenix, AZ 85012

CALL FOR CONSULTATION 602-265-5200
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