'United States v Microsoft: High-tech Antitrust'. This article considers some of the substantive issues that have been raised by the case brought against Microsoft and that call into question the application of competition law to high-technology industries. Drawing arguments from both the United States and European Union jurisdictions the article focuses in particular on the relationship between intellectual property and competition law. Consideration is also given to product development and bundling, and to predation through innovation. In conclusion the author suggests that competition laws should continue to be applied to this sector, but that traditional analysis needs to be refined, and that intent should be more carefully considered.