The 90 year old, who was played by Robert De Niro in classic 1980 movie Raging Bull, fell over and ruptured his pubic bone, according to New York Post gossip column Page Six.
He has now been released from hospital and doctors have given him permission to continue with a run of his Lady and the Champ show, which co-stars his fiancee Denise Baker.
The run begins on 19 July (12) at New York City's Richmond Shepard Theatre.
News of LaMotta's hospitalisation comes shortly after it was revealed he is facing a lawsuit over an upcoming Raging Bull sequel.
Studio bosses at MGM have filed suit against the former sportsman, alleging they should have been offered the chance to develop the follow-up, which is based on his 1986 sequel book.