Released in North America as "The Professional", the international version was simply known as "Leon" and was approximately 20 minutes longer. It included footage of a few scenes, including the following:
According to director Luc Besson, he didn't mind at all making the cuts to the film for a North American audience because he understood the environment here probably wouldn't be as open to these themes as people would elsewhere. Plus, he had a great relationship with the producers so he had no arguments with them on this particular case.
Oops...I should also point out that this is Natalie Portman's on-screen debut.