South Park: Bigger Longer & Uncut (1999)
In The Guinness Book Of World Records 2001 this film was said to have the most profanity used in an animated film. It contained a total of 399 swear words (the word "f**k" was used 146 times). 199 offensive gestures and also contained 221 acts of violence.
http://www.imdb.com/title/tt0158983/trivia
Most prolific use of the "F" word:
Two movies beat out Casino with 824 & 428 uses.
Casino - 422 times
Born on the Fourth of July - 289 times
The Big Lebowski - 281 times
Pulp Fiction - 271 times
Dead Presidents - 247 times
Boondock Saints - 246 times
GoodFellas - 246 times
Jay and Silent Bob Strike Back - 228 times
Scarface (1983) - 218 times
American History X - 205 times
I'm not including the link as I'd just have to delete it due to content...HOWEVER, if one GOOGLES each of the above lines...you'll find plenty of sources.