Continuity: When Serpico finds three black men raping a girl in the park, one of them cuts the girls face slightly and the cut is very visible. The camera then cuts away then back and the cut and blood is gone.

Continuity: In the scene where Serpico is in his apartment speaking to his girlfriend explaining how hard it's been to be an honest cop, he is drinking what appears to be a full glass of white wine. In the following shot of the both of them, Serpico sets up two unused glasses, opens a bottle of wine and pours it into the two glasses. His original full glass of wine is nowhere to be seen.