How to Establish Paternity in Colorado
Reviewed by DocDraft Legal Team · Colorado · Last updated 2026-09-12
In Colorado, establishing paternity means legally identifying a child's father so the child gains rights to support, custody and parenting time, inheritance, health coverage, and benefits. Colorado follows the Uniform Parentage Act (C.R.S. Title 19, Article 4). Unmarried parents who agree can sign a Voluntary Acknowledgment of Paternity, which becomes a legal finding of paternity on the earlier of the federal 60 days after signing or the date of a related administrative or judicial proceeding, after which it can be challenged only for fraud, duress, or mistake of material fact (C.R.S. 19-4-105). When parents disagree, a court decides parentage. Colorado's timing rules are load-bearing and unusual. An action to establish the father-child relationship may be brought at any time before the child's 18th birthday, and a child whose paternity has not been determined may bring one any time before the child's 21st birthday (C.R.S. 19-4-108). But an action to declare that a presumed father-child relationship does NOT exist must be brought within a reasonable time after learning the relevant facts and, in any event, no later than five years after the child's birth (C.R.S. 19-4-107). A man is presumed the father if he was married to the mother and the child is born during the marriage or within 300 days after it ends (C.R.S. 19-4-105), and genetic tests showing a 97 percent or higher probability of parentage also create a presumption, rebuttable only by clear and convincing evidence. Attorney review of your situation is available through DocDraft.
Find out where you stand in Colorado
Where are you in establishing paternity?
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What are the ways to establish paternity in Colorado?
Unmarried parents who agree can sign a Voluntary Acknowledgment of Paternity, which becomes a legal finding of paternity and lets the father be added to the birth certificate. If parents disagree, a court determines parentage under C.R.S. 19-4-107, usually after ordering genetic testing.
How long do I have to establish paternity in Colorado?
An action to establish the father-child relationship may be brought at any time before the child's 18th birthday, and a child whose paternity has not been determined may bring one any time before turning 21 (C.R.S. 19-4-108). These are the outer limits for opening a parentage case in Colorado.
Is there a deadline to disprove paternity in Colorado?
An action to declare that a presumed father-child relationship does not exist must be brought within a reasonable time after learning the relevant facts, and in no event later than five years after the child's birth (C.R.S. 19-4-107). That five-year limit is a firm cutoff.
What genetic-testing result establishes paternity in Colorado?
Under C.R.S. 19-4-105, a man is presumed the father when genetic or other inherited-characteristic tests administered as provided in C.R.S. 13-25-126 show he is not excluded and the probability of his parentage is 97 percent or higher. The presumption is rebutted only by clear and convincing evidence.
Colorado paternity law at a glance
Colorado's Uniform Parentage Act (C.R.S. Article 4) has two timing rules worth comparing. To establish the father-child relationship, an action may be brought before the child's 18th birthday, and a child whose paternity has not been determined has until the 21st birthday (C.R.S. 19-4-108). To declare that a presumed relationship does not exist, the action must be brought within a reasonable time after learning the facts and no later than five years after birth (C.R.S. 19-4-107). Colorado's 97 percent genetic threshold sits between the 95 percent some states use and the 99 percent used by others. A man is presumed the father if married to the mother and the child is born during the marriage or within 300 days after it ends, or if genetic tests under C.R.S. 13-25-126 show a 97 percent or higher probability of parentage. Any presumption is rebutted only by clear and convincing evidence (C.R.S. 19-4-105).
Establishing Colorado paternity for a child born to unmarried parents
Suppose a child is born in Colorado to unmarried parents who agree on the father. Both sign a Voluntary Acknowledgment of Paternity at the hospital; it becomes a legal finding of paternity on the earlier of 60 days after signing or a related support proceeding (C.R.S. 19-4-105). If one parent reconsiders during the federal 60-day window, the acknowledgment is not yet final; afterward it can be challenged only for fraud, duress, or mistake of material fact. Had the parents instead disputed parentage, either could ask the court for genetic testing, where a 97 percent or higher probability of parentage creates a presumption (C.R.S. 19-4-105 and 13-25-126). Because they want to establish the relationship, the action may be brought before the child's 18th birthday (C.R.S. 19-4-108). Had a husband instead sought to declare a presumed relationship nonexistent, he would face the five-year-after-birth limit (C.R.S. 19-4-107). Attorney review is available through DocDraft.
Relevant Laws
C.R.S. 19-4-105 (presumption of paternity and genetic-testing threshold)
Provides that a man is presumed the natural father if he and the mother are or were married and the child is born during the marriage or within 300 days after it ends, or if genetic tests under C.R.S. 13-25-126 show a 97 percent or higher probability of parentage, and that a presumption may be rebutted only by clear and convincing evidence. It also makes a voluntary acknowledgment a legal finding on the earlier of 60 days or a related proceeding.
C.R.S. 19-4-107 (who may bring an action and when)
Provides that an action to declare the existence of a presumed relationship may be brought at any time, but an action to declare its nonexistence must be brought within a reasonable time after learning the relevant facts and no later than five years after the child's birth.
C.R.S. 19-4-108 (statute of limitations)
Provides that an action to determine the father-child relationship may be brought at any time before the child's 18th birthday, and that an action brought by a child whose paternity has not been determined may be brought at any time before the child's 21st birthday.
C.R.S. 13-25-126 (genetic testing in parentage cases)
Governs the administration and admissibility of genetic and other inherited-characteristic tests used to determine parentage, referenced by C.R.S. 19-4-105 for the 97 percent probability presumption.
42 U.S.C. 666(a)(5) and 45 CFR 303.5 (federal voluntary acknowledgment and 60-day rescission)
Federal law requires every state child-support program to offer an in-hospital voluntary paternity acknowledgment, a 60-day period to rescind it, and a rule that after 60 days the acknowledgment may be challenged only for fraud, duress, or material mistake of fact.
Colorado Child Support Services
Colorado Child Support Services, part of the Colorado Department of Human Services, can open a case to establish parentage and support and administers the Voluntary Acknowledgment of Paternity process.
Regional Variances
Colorado paternity rules at a glance
Voluntary path
Unmarried parents establish parentage by signing a Voluntary Acknowledgment of Paternity, usually at the hospital, which becomes a legal finding of paternity and lets the father be added to the birth certificate (C.R.S. 19-4-105).
Rescission window
The acknowledgment becomes final on the earlier of the federal 60 days after signing or a related administrative or judicial proceeding (C.R.S. 19-4-105). After that, only fraud, duress, or mistake of material fact will set it aside.
Marital presumption
A man is presumed the father if he was married to the mother and the child is born during the marriage or within 300 days after it ends (C.R.S. 19-4-105), rebuttable only by clear and convincing evidence.
Deadlines to establish and disprove
Establishing the relationship may be brought before the child turns 18, or 21 if the child brings it and paternity is undetermined (C.R.S. 19-4-108); disproving a presumed relationship must be brought no later than five years after birth (C.R.S. 19-4-107).
Genetic-testing threshold
Genetic tests under C.R.S. 13-25-126 showing a 97 percent or higher probability of parentage create a presumption of paternity, a threshold between the 95 percent and 99 percent used elsewhere.
Who administers it
Colorado Child Support Services, part of the Colorado Department of Human Services, opens parentage and support cases; disputed parentage is decided by the court, which may order genetic testing.
Suggested Compliance Checklist
Confirm whether a marital presumption applies
Before signing or filing anything days after startingDetermine whether the child was born during the marriage or within 300 days after it ended, which makes the husband the presumed father (C.R.S. 19-4-105). If so, an action to declare the relationship does not exist must be brought no later than five years after birth (C.R.S. 19-4-107).
Get genetic testing if biological parentage is uncertain
Before signing an acknowledgment days after startingBecause the acknowledgment becomes a legal finding, obtain genetic testing first if there is any doubt. Under C.R.S. 19-4-105 and 13-25-126, a 97 percent or higher probability of parentage creates a presumption of paternity.
Sign the Voluntary Acknowledgment of Paternity
At the hospital or a local office days after startingUnmarried parents who agree sign a Voluntary Acknowledgment of Paternity, which becomes a legal finding of paternity once filed (C.R.S. 19-4-105). Keep a copy. Attorney review of your paternity matter is available through DocDraft.
Track the federal 60-day window
Within 60 days of signing days after startingThe acknowledgment becomes final on the earlier of 60 days after signing or a related administrative or judicial proceeding (C.R.S. 19-4-105). After that, it can be challenged only for fraud, duress, or mistake of material fact.
File a parentage action if parents disagree
Establish before the child turns 18 days after startingIf parents do not agree, ask Colorado Child Support Services to open a case or file an action under C.R.S. 19-4-107. To establish the relationship, file before the child's 18th birthday (C.R.S. 19-4-108). The court can order genetic testing and enter a judgment.
Keep records of the acknowledgment, testing, and orders
Ongoing days after startingSave copies of the signed acknowledgment, any genetic-test results, and court papers, and calendar the federal 60-day window, the 18th-birthday cutoff to establish, and the five-year limit to disprove a presumed relationship (C.R.S. 19-4-107) so you do not miss a right-forfeiting date.
| Task | Description | Document | Days after starting |
|---|---|---|---|
| Confirm whether a marital presumption applies | Determine whether the child was born during the marriage or within 300 days after it ended, which makes the husband the presumed father (C.R.S. 19-4-105). If so, an action to declare the relationship does not exist must be brought no later than five years after birth (C.R.S. 19-4-107). | - | Before signing or filing anything |
| Get genetic testing if biological parentage is uncertain | Because the acknowledgment becomes a legal finding, obtain genetic testing first if there is any doubt. Under C.R.S. 19-4-105 and 13-25-126, a 97 percent or higher probability of parentage creates a presumption of paternity. | - | Before signing an acknowledgment |
| Sign the Voluntary Acknowledgment of Paternity | Unmarried parents who agree sign a Voluntary Acknowledgment of Paternity, which becomes a legal finding of paternity once filed (C.R.S. 19-4-105). Keep a copy. Attorney review of your paternity matter is available through DocDraft. | - | At the hospital or a local office |
| Track the federal 60-day window | The acknowledgment becomes final on the earlier of 60 days after signing or a related administrative or judicial proceeding (C.R.S. 19-4-105). After that, it can be challenged only for fraud, duress, or mistake of material fact. | - | Within 60 days of signing |
| File a parentage action if parents disagree | If parents do not agree, ask Colorado Child Support Services to open a case or file an action under C.R.S. 19-4-107. To establish the relationship, file before the child's 18th birthday (C.R.S. 19-4-108). The court can order genetic testing and enter a judgment. | - | Establish before the child turns 18 |
| Keep records of the acknowledgment, testing, and orders | Save copies of the signed acknowledgment, any genetic-test results, and court papers, and calendar the federal 60-day window, the 18th-birthday cutoff to establish, and the five-year limit to disprove a presumed relationship (C.R.S. 19-4-107) so you do not miss a right-forfeiting date. | - | Ongoing |
Frequently Asked Questions
Establishing paternity in Colorado means legally identifying a child's father so the child can receive support, custody and parenting time, inheritance, health coverage, and benefits. It can be done by signing a Voluntary Acknowledgment of Paternity or through a court action to determine parentage under C.R.S. 19-4-107.
Unmarried parents who agree can sign a Voluntary Acknowledgment of Paternity, which becomes a legal finding of paternity. If parents disagree, a court determines parentage under C.R.S. 19-4-107, generally after ordering genetic testing that meets the state threshold of a 97 percent or higher probability of parentage (C.R.S. 19-4-105).
An action to establish the father-child relationship may be brought at any time before the child's 18th birthday, and a child whose paternity has not been determined may bring one any time before turning 21 (C.R.S. 19-4-108). This establishing window is separate from the shorter deadline that applies to disproving a presumed father.
An action to declare that a presumed father-child relationship does not exist must be brought within a reasonable time after learning the relevant facts, but no later than five years after the child's birth (C.R.S. 19-4-107). That five-year limit is a firm cutoff.
Under C.R.S. 19-4-105, a man is presumed the father if he and the mother are or were married and the child is born during the marriage or within 300 days after it ends. The presumption is rebutted only by clear and convincing evidence, or by a court decree naming another man as father.
Only briefly. A Voluntary Acknowledgment of Paternity becomes a legal finding on the earlier of 60 days after signing, the federal window, or a related administrative or judicial proceeding (C.R.S. 19-4-105). After that, it can be challenged only for fraud, duress, or mistake of material fact.
Under C.R.S. 19-4-105, tests administered as provided in C.R.S. 13-25-126 that show the man is not excluded and that the probability of his parentage is 97 percent or higher create a presumption of paternity, rebuttable only by clear and convincing evidence.
Colorado Child Support Services, part of the Colorado Department of Human Services, can open a case to establish parentage and support. When parentage is disputed, the court decides it under C.R.S. 19-4-107 and can order genetic testing before entering a judgment.
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