They got married when she was 15 and R Kelly was 27.
The certificate, leaked at the time, listed her age as 18.
Kelly is facing several sexual abuse charges with trials in Chicago and New York next year. He denies wrongdoing.
The latest criminal indictment was filed by federal prosecutors in Brooklyn, New York, and expands on charges filed against him in July.
They say he and his entourage headed up a racketeering operation, across two decades, which recruited women and under-age girls for illegal sexual activity.