According to TMZ, the Frasier actor filed legal documents with the Los Angeles Country Superior Court, in order to win full custody of their children - Mason, 9, and Jude, 6.
The actor has apparently rejected a 50/50 custody offer from his ex-wife Camille. He currently lives in Chicago with his wife Katye Walsh, whom he married in February.
Camille Grammer had previously said how she was "hurt" by the actor's recent marriage so soon after their own divorce.
She has opted to keep her ex-husband's surname.