The first few years of the 90s have been extremely important for the development of software copyright both in the United States and Europe. In the United States, major decisions redefined the idea/expression dichotomy in different cases. In Europe, countries are still in the process of harmonizing their national laws with the EC Software Directive. The study compares traditional and evolving copyright standards as applied to computer programs on both sides of the Atlantic. It may well be said that recent case law has brought America closer to Europe. On the other hand, American experience turns out to be a useful guideline for distinguishing between the concepts of idea and expression in the sense of the software directive.