Revealing mistake: Right at the start of the movie, Tom Ewell is in Central Station kissing his wife and son goodbye. When they are just about to leave, watch a kid on the left of the screen. He can't help staring at the camera.
Continuity mistake: In the very last scene Marilyn Monroe throws Tom Ewell the shoes he forgot to put on. He thanks her and waves, with one shoe still held in his hand. He turns round and walks away, with both shoes on.