General Terms and Conditions are vitally important in this age of mass production and mass consumption. There is a significant risk of litigation where General Terms and Conditions are found to be invalid. The present work concludes that not only the listed institutions in § 3 UKlaG are able to claim against the provider of invalid conditions, but also his competitors due to §§ 8 et seq. German UWG. The rationale for this conclusion derives from the requirements of Directive 2005/29/EG relating to unfair commercial practices. Besides providing an analysis of the requirements of the Directive the author addresses the problems of implementation of the Directive in German law. Following this analysis it becomes apparent that a renunciation of the common German guidelines for the law of unfair commercial practices is necessary.