Introduction. The article investigates the boundaries of a multiparty system in constitutional law. Analyzes the limitations of a multiparty system adopted in the democratic countries of Europe. Theoretical analysis. The author explores the limits of political parties, enshrined in the Constitution and the law, revealing contradictions wording. Particular attention is given to such a restriction in the activities of political parties, as the prohibition of extremist activity. The article points out the contradictions in the understanding of extremist activity, which is enshrined in various federal laws. Indicated on the mixing of concepts such as terrorism and extremism. It is concluded that the category of «discrimination» act as an independent and not always be regarded as extremism. It is proved that the elimination of the political party on the specified in the law on political parties, the grounds, the reduction due to the multi-party opposition to extremism and acts as a serious and preventive measures. Conclusion. The analysis of Russian legislation, the author comes to the conclusion that the vagueness of the wording might lead to unnecessary restriction of the activities of political parties and their elimination as opponents of the constitutional order, which is unacceptable in a democratic, politically pluralistic state.