The law against unfair competition is traditionally understood in countries of the Alpine legal system as extraordinary and unconventional. Unlike other legal disciplines, it does not rely on black-letter law; it is less formal and less legislatively elaborative in detail. Thus, progress and development in this area is not a matter for the legislator but for broad practically-driven doctrinal work connected to contemporary case law. When the Internet brought new opportunities in the development of business ventures, Czech law against unfair competition did not react with legislative changes but by the further development of standard interpretational patterns. In this article, we will briefly describe the grounds as well as recent related developments in the Czech law against unfair competition connected to unfair business practices on the Internet.