The research of the political discourse is of particular interest for contemporary Linguistics since it is based on the study of the connection between politics and language. This connection is important for politics from the point of view of those functions that the former plays in the society and which have a direct reference to the language use. The political discourse and its functions are considered from the theoretical point of view in the paper and the practical analysis of slang, its pragmatic aspect based on the study of semantics and sources of slang, and its role in the discourse is made. To do this such methods as the descriptive one, the comparative one and the method of component analysis were used. The political discourse represented in the speech and interviews of the president of the Russian Federation V.V. Putin to mass media was considered. It was found out that the political discourse is addressed to the general public and plays argumentative and persuasive functions. Slang is used to achieve the following goals: 1) to strengthen the political discourse functions; 2) to make speech more emotionally coloured; 3) to include joke elements into the speech; 4) to characterize (positively or negatively) those processes or actors that are mentioned by the president. The sources of slang in the political discourse include word formation models (compounding, affixation), borrowings from other languages as well as the native language.