In this paper, the author deals with the question of realization of guaranteed freedom of peaceful assembly and the prohibition of discrimination on the basis of sexual orientation. The prohibition of discrimination and freedom of peaceful assembly are prescribed by international documents and domestic law. The main emphasis will be on the prohibition of the Pride Parade that was to be held in Belgrade in October 2011 and on the rights and freedoms of the LGBT population that were consequently violated. However, on 22 December 2011 the Constitutional Court of Serbia upheld a constitutional complaint lodged by the organizers of the Pride Parade in 2009. The Constitutional Court ruled that the competent authorities in Serbia banned the 2009 Pride Parade in violation of the Serbian Constitution. This decision is of great importance for human rights protection in Serbia and the cornerstone judgment regarding the prohibition of discrimination on the basis of sexual orientation and realization and protection of human rights and fundamental freedoms in our country.