In this article the authoress discusses Czech infinitival structures to illustrate the classification and methods of analyses used in generative framework. Introducing the null category of PRO she shows the distinctions between Raising and Control verbs, between ECM verbs and PROOBJ structures. She also describes the process of restructuralization and the diagnostics of the phenomena in more detail. The authoress mentions some existing studies of Czech infinitives and the most influential analyses in English, Italian and German. She concludes that the present-day analyses of infinitives are still in many aspects problematic and they depend on the development of the field, including the format of the structure and assumptions concerning the distribution of thematic roles.