Recent years have seen the emergence of various projects for post-Soviet economic integration: the European Union (EU) has developed its Eastern Partnership, while Russia has put forward the Eurasian Economic Union (EAEU). Post-Soviet states and, most notably, the countries of the 'shared neighbourhood' between Russia and the EU find themselves in a delicate position, as they are influenced and pressured by both of these actors for closer cooperation. The events in Ukraine have made clear that the resulting consequences of 'choosing a side' can be devastating for a country and that a new approach towards the integration of the post-Soviet space is necessary. This thesis analyses, firstly, the on-going process of post-Soviet economic integration, its main policies and instruments. Secondly, it focuses on the countries concerned by these integration efforts, how they are affected and which domestic needs and interests they have to consider in their decision making process. The case study concentrates on the South Caucasus, a geopolitically important area where peace and security are fragile due to frozen conflicts. The research has shown that the South Caucasus displays the same fragmentation as the overall post-Soviet space: Armenia has joined the EAEU, Georgia has signed the Association Agreement (AA) and Azerbaijan is pursuing a relatively independent stance. Furthermore, they each illustrate the crucial shortcomings of both EU and Russian approaches towards post-Soviet economic integration, such as the lack of flexibility (especially the AA proposed by the EU), coherence and the willingness to make concessions. Finally, it has been shown that, in decisions relating to cooperation with either the EU or Russia, political and security considerations are prevailing.