Paternity in Colorado: what a paternity case is, and how it works.

What a paternity case is, and what it is not.

Colorado’s official word is parentage, and the case is a petition to establish parentage. Everyone, including judges, still says paternity. The comparison with a divorce tells you most of what you need to know.

Side by side.

How paternity is established: four ways.

A father becomes a legal father one of four ways. Which one applies decides how easy the rest of the case is, and how hard it is to undo.

The hospital form, and its sixty days.

Three questions before anyone signs: Are you certain? Is she married to someone else? Was the child conceived with a donor?

The form takes five minutes and lasts a lifetime. Once the state files it, the father has every right and duty of a parent, and support can be ordered without anyone proving paternity again. What the form does not do is set a schedule: parenting time is agreed between you or decided by a court later.

Sixty days, or less. Either parent can cancel it for any reason within sixty days of signing, or until a court case about the child is filed, whichever comes first. After that it can be undone only for fraud, duress or a serious mistake of fact, and the person challenging it has to prove it while support keeps running. So: if there is any doubt at all, test first. The form can wait a month; the doubt cannot be signed away.

If the mother is married to someone else, her husband must also sign a form denying paternity before the acknowledgment can be filed.

Why the drugstore kit does not count.

A mail-in kit tells you the answer; it does not prove it. Nobody watched the swabs being taken, so a court cannot know whose DNA was tested. The state’s own brochure says over-the-counter tests cannot be used as evidence. A legal test costs about $200 to $500 as of September 2026 and settles the question for everyone. A prenatal test from the mother’s blood exists and costs over $1,000; use it to make decisions during the pregnancy, and expect the court to order a test after the birth anyway.

Who can file, and when.

Either parent, the county, or the child. There is no rush written into the law, but there are two situations with short clocks, and every month without an order shapes the case.

The short version.

There is no deadline for most paternity cases. There is a cost to waiting: the parent with the child has the schedule, and every month makes it the normal one.

What the court can decide, and what it cannot.

Once the father is named, the case turns into what every court does for children: a parenting plan and a support order. Two things that are different from a divorce are worth knowing.

What a paternity case can do.

What it cannot do.

Back support: the case that reaches furthest back.

A divorce reaches back to the filing. A paternity case can reach back to the birth, on facts a parent can prove.

In a divorce or custody case, support for the past reaches back only to the day you separated, filed or served the papers. A paternity case can reach back to the child’s birth, and the judge can add the reasonable costs of the pregnancy and the delivery and the DNA test. It is not automatic. Since February 2026 the judge must weigh the father’s ability to pay both the past and the current support, whether anyone ever asked him for support, whether he dodged being served, what he actually provided in money, diapers, food, clothing and gifts, and whether he was kept from the child. Each of those is something a parent can document, starting now.

A parent owed years of support who files a custody case instead of a paternity case may give up everything before the filing date. Which case to file is the first decision, and it is worth a consultation on its own.

Parenting time: the same rules as a divorce, once the father is named.

No preference for mothers, no preference for fathers; the schedule and the decision-making are decided on the child’s best interests, and asking for a DNA test cannot be held against you. The order that names the father creates no schedule by itself. Ask for parenting orders in the same case, propose a real plan, and live it while the case is pending.

The county child support office: what it does, and what it will not.

Every Colorado county has a Child Support Services office. When the goal is support and nobody really disputes who the father is, it is the cheapest route there is: no application fee, and the DNA test paid up front.

The metro offices, as of September 2026: Denver 720-944-2960, Arapahoe 303-636-1170, Jefferson 303-271-4300, Douglas 303-814-7145; or apply online at the state’s child support site. If you are afraid of the other parent, say so before anything is filed. The state’s own brochure warns that establishing paternity can raise safety concerns for survivors of domestic violence, and a parent with good cause is excused from cooperating. The National Domestic Violence Hotline is 1-800-799-7233. See also Domestic Violence & Divorce.

A paternity case, step by step.

Most cases are settled by agreement once the test is back. A contested one goes to a hearing in front of a judge, never a jury.

1. Step 1
   File.

   A petition to establish parentage (the Judicial Branch’s form is JDF 1501), naming every man who might be the father. The filing fee is $268 on the current fee list; confirm with the clerk. Tick the boxes for back support and birth expenses if you want them.

2. Step 2
   Serve, and the automatic rules start.

   For the 120 days after service, neither of you may take the child out of Colorado, harass the other, or cancel the child’s health insurance without notice. The other parent files a short answer admitting or denying paternity.

3. Step 3
   The DNA test.

   Ordered by the court on request, or done by agreement. Get it done before the final order; afterward the only remedy is a two-year motion. If the result is 97 percent or more, temporary support can start right away.

4. Step 4
   Paternity is decided.

   By agreement, which is most cases, or after a hearing. The order names the father for every purpose.

5. Step 5
   Support and the parenting plan.

   Both parents file financial statements, the guideline worksheet sets support, and a parenting plan is agreed or decided. Most metro courts send parents to mediation and a parenting class first.

How long. An agreed case with a clean test can be finished in a few months. A contested parenting plan takes as long as any custody case, often the better part of a year, depending on the county and whether an evaluator is appointed.

If you are not sure you are the father: what to do, in order.

The rules get stricter at each step, so the cheapest moment to act is always now.

Never refuse a court-ordered test. The court can rule that you are the father because you refused, and the county issues a default order. The test is the only thing that protects a man with doubts.

Unmarried fathers: before the order, and after it.

Colorado is not a mother state. No law gives the mother custody by default. But until paternity is established and a parenting plan is entered, the mother is the only legal parent, and that is what a father is up against.

What to do, and when.

Establish paternity early, then ask for parenting orders in the same case. An adoption plan runs on a thirty-five-day clock.

Early. Sign the acknowledgment if you are both sure; test first if either of you is not; file if she will not sign. Until there is a parenting order, the parent who has the child has the schedule, and each month of it becomes the normal one a judge is asked to change.

If she is married. Her husband is the presumed father, and the acknowledgment needs his signed denial. You can still file a case; the Colorado Supreme Court has said a biological father cannot be shut out just because the mother is married. But a DNA match does not end that case. The court weighs the child’s interests, and biological fathers have lost to husbands who raised the child.

If an adoption is planned. File the paternity case within thirty-five days of the birth, or of learning you are likely the father; in an expedited placement, within twenty-one days of notice. There is no registry to sign instead. See Step-Parent Adoption for the other side of that case.

Six things people get wrong.

What to bring, and the law behind this page.

For the lawyers, the statutes. The parentage article is C.R.S. § 19-4-101 and following: the presumptions, C.R.S. § 19-4-105; the acknowledgment and its sixty days, C.R.S. § 19-4-105(2); who may file and the deadlines, C.R.S. § 19-4-107 and C.R.S. § 19-4-108; filing before the birth, C.R.S. § 19-4-105.5(3); genetic testing and refusal, C.R.S. § 13-25-126; the order and back support, C.R.S. § 19-4-116; fees, C.R.S. § 19-4-117; parenting orders, C.R.S. § 19-4-130; the two-year DNA set-aside, C.R.S. § 19-4-107.3; the county’s administrative process, C.R.S. § 26-13.5-101 and following; the adoption clocks, C.R.S. § 19-5-105(3.1)(c)(I) and C.R.S. § 19-5-103.7. The leading cases on a husband’s presumption against a biological father are N.A.H. v. S.L.S., 9 P.3d 354 (Colo. 2000) and In re Marriage of Ohr, 97 P.3d 354 (Colo. App. 2004); on back support to the birth, People ex rel. B.W., 17 P.3d 199 (Colo. App. 2000); on custody before the birth, People in Interest of G.C.M.M., 2020 COA 152.

The paternity questions that fill my inbox.

Related: Child Support  ·  Parental Responsibilities  ·  Parenting Time  ·  Modifying Child Support  ·  Mediation