Paternity in Montana

Learn the basics of paternity and how to establish paternity for your child in Montana.

This article explains the process of legally establishing "paternity," which refers to the identity of a child's father. It may be especially important to establish paternity in cases where it's not automatically established at birth, such as when a child is born out of wedlock or when the mother is married and her husband is not the child's father. The process can be done voluntarily, by the child's parents, or by filing a paternity case in court.

If you are trying to establish paternity and have questions about your case, you should contact an experienced family law attorney in your area.

Ways to Establish Paternity

Through a Marriage

A man is presumed to be a child's natural father if:

  • the man and the child's natural mother were married (either common law marriage or solemnized marriage) when the child was born
  • the child was born within 300 days after the marriage ended due to death, annulment, divorce or court-ordered decree of separation
  • before the child's birth, the man and the child's natural mother tried to marry each other (even though the marriage turned out to be invalid), and the child was born within 300 days of a separation, annulment, dissolution or the death of either parent
  • after the child's birth, the man and the child's natural mother were married, or attempted to marry, and
    • the man acknowledged his paternity in writing and filed it with the Montana Bureau of Vital Records
    • the man gave consent to be named as father on the child's birth certificate, or
    • the man is obligated to support the child under a voluntary written promise or court order.

Voluntarily Acknowledging the Child

A father may also voluntarily establish paternity by any of the following methods.

  • the father may acknowledge paternity in an affidavit signed by the child's natural mother and filed with the Montana Bureau of Vital Records, or
  • while the child is younger than 18, the man receives the child into his home and holds the child out as his own.

When both parents voluntarily sign the paternity acknowledgement form, the father's name will then be put on the child's birth certificate, and the child may be given the father's last name. The acknowledgement can be signed while the mother and baby are still in the hospital. These forms are generally available at the hospital when the child is born, or afterwards through the Montana Department of Public Health and Human Services. This voluntary acknowledgement can be rescinded by the father within one year of signing, or by a court order.


A mother, father, or child can file a court action asking the Montana district court to determine paternity. Usually, this happens when a father refuses to voluntarily sign an acknowledgement, or when a mother and father do not agree on paternity. The Child Support Enforcement Division of the Montana DPHHS can also file a paternity case on behalf of a child.

A paternity case cannot be decided by the court until after the child is born. Often, genetic testing is ordered for the mother, father and child in order to determine the identity of the father. When a blood test shows a 95% or higher statistical probability of a certain man being the father, the court will find that man is the natural father, and his name will be placed on the child's birth certificate. A paternity case can be filed with the court any time before the child turns 18, or it can be brought by the child up until he or she reaches age 21.

What are the Benefits of Establishing Paternity?

Establishing paternity gives children that are born out of wedlock the same rights to support and benefits given to children born of a marriage. It also ensures the child knows about both sides of his or her family, including any special health concerns that might run in the father's side.

Establishing paternity also ensures that either parent can seek child support from the other. It will allow a child to be placed on the father's health insurance, if the father has such insurance available. When the father dies, paternity ensures that the child can inherit from the father and his family. The child can also receive Social Security and Veteran's benefits on his or her father's record, if such benefits are available.

If a father doesn't take steps to acknowledge his paternity, he could lose the right to request custody or visitation with his child. He may even lose the right to receive notice of court proceedings regarding his child.


Montana Judicial Branch - Information on Paternity

Montana DPHHS - Paternity Information for Parents

Montana DPHHS - Paternity Acknowledgement and Withdrawal of Acknowledgement Forms

Montana Code Ann. § 40-6-105 - Presumption of paternity

Montana Code Ann. § 40-6-108 - Statute of limitation

Montana Code Ann. § 40-6-202 - Legitimacy of children

Montana Code Ann. § 40-6-203 - Child legitimized by marriage of parents

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