The article is devoted to the study of problems of synergism and the formation of a synergistic effect in the socio-economic development of industrial enterprises. It is emphasized that in the conditions of modern challenges, the issue of ensuring the efficiency of economic systems and determining the impact of interaction between economic systems on their effectiveness, i.e., the formation of a wide range of synergistic effects, is becoming actualized. It has been proven that industrial enterprises are a key sector of the economy. The effective functioning of industrial enterprises affects the improvement of the welfare of society, the reduction of unemployment and, accordingly, the increase of employment of the population. It is substantiated that industrial enterprises are participants in the socio-economic development of the country, as aresult of their activity there is a synergistic effect, which affects the increase of the country's competitiveness. The economic indicators of the development of industrial enterprises of Ukraine were analyzed and it was proved that the relevance of synergism is determined by the special state of complex economic systems in conditions of instability, equilibrium and the dynamics of their selforganization. The place and role of synergism in the socio-economic development of industrial enterprises are highlighted. It is noted that synergy is manifested as a result of the integrated interaction of a number of factors, namely, the interaction of individual areas of activity, innovative, investment, and intellectual factors. It is emphasized that the very existence of positive feedback is a prerequisite for revolutionary transformations in the process of managing the socio-economic development of industrial enterprises. A multifactorial linear model of the index of the sale of industrial products was built, based on which the influence of profit, current costs and the volume of investments of industrial enterprises on the formation of a synergistic effect was estimated. It is proposed that in order to strengthen synergistic effects in the planning of socio-economic development of industrial enterprises in Ukraine, special attention should be paid to reducing operating costs.