Illinois Affidavit by Biological Mother (Legitimation) (VR 171)
Official state formParentage and paternityForm VR 171Free downloadLast verified November 10, 2026
Notarized affidavit by the biological mother who married the father after the child was born. It supports a new birth certificate from the Illinois Division of Vital Records that names the father.
Who can use this form
- The biological mother who married the biological father after the child was born.
- The office asks parents to call first if a parent is deceased, another man is on the record, the mother was married to another man, or the child was born outside Illinois.
What to send with it
- This affidavit, completed in ink or typed and signed in front of a notary public.
- The father's affidavit.
- A certified copy of the parents' marriage record from the county clerk. Photocopies are not accepted.
- A copy of a non-expired government-issued photo ID.
- The fee, by check or money order payable to the Illinois Department of Public Health or IDPH.
- One set of forms for each child.
Where to send it
- Mail to
- Illinois Department of Public Health Division of Vital Records 110 West Lawrence Avenue Springfield, IL 62704-2610
- State fee
- $15 per child, which includes one certified copy. Additional copies ordered at the same time are $2 each. The fee is stated on the Legitimation Forms instructions (VR 170), not on this affidavit.
- Typical processing
- Approximately 12 weeks from receipt for mailed requests, per the notice on the office's records pages.
- Form revision
- REV (08/26)
- Source
- Official government page