The paper discusses the possibility of deepening Serbia's cooperation with Russia and with international organizations and the integration processes that Russia conducts in the post-Soviet space. Serbia is a military neutral country, but it has certain forms of cooperation with both NATO and the CSTO, where it has a status of an observer. The Shanghai Cooperation Organization also provides various opportunities for cooperation, including statuses of an observer, partner and a guest. In the domain of economy, the Eurasian Union is interesting for Serbia, which already achieved a free trade agreement in 2019, which was then ratified. The full members of the Eurasian Union generate about $ 2 trillion in GDP and have about 185 million inhabitants, as well as significant economic capacities and natural resources. An important factor for deepening Serbia's cooperation with integrations in the post-Soviet space is the fact that they are friendly countries led by Russia, which can be a significant factor in the realization of essential Serbian interests.