Subject. The article investigates the impact of foreign economic activity on socio-economic development of subjects of the Volga Federal District. Objectives. The aim is to develop and test our original methodology for quantifying the impact of foreign economic activity on region’s socio-economic development, using the integral index of foreign economic activity elasticity, to identify differences in the impact of foreign economic activity on the economies of regions with different sectoral structures. Methods. We used methods of analyzing theoretical sources, comparative and structural-dynamic analysis, calculation of elasticity coefficients, multipliers of production and employment, and aggregation of these indicators into an integral index. Results. The impact of foreign economic activity on socio-economic development of regions of the Volga Federal District is heterogeneous: in some leading regions it has a pronounced positive impact on GRP, industrial production, and employment, while in other subjects the elasticity is weak or even negative. We recorded a decrease in employment in export-oriented industries against the background of growth or stability of export indicators, reflecting structural and technological shifts. The findings differ significantly from the data presented in other studies and emphasize the role of regional specifics and institutional factors. Conclusions. The developed methodology enables to comprehensively assess the said impact and identify not only growth drivers, but also risk areas. Practical application of the index of foreign economic activity elasticity can contribute to the improvement of regional policy, monitoring the effectiveness of export-oriented industries, and formation of targeted support measures.