In a dynamically developing market, intensifying competition, it becomes clear that cooperation provides business structures with more strategic advantages. Top management of many enterprises is aware of the need for interfirm integration. This article is devoted to the study of the characteristic features of one of the most prospective forms of economic companies' integration. Due to its growing flexibility in terms of contradictory economic trends and conditions strategic alliances need a deep study for solving main problems of their functioning. To this end the author provides the common definition of strategic alliance and distinguishes the key factors for success and failures of strategic alliances which can be practically used by managers for planning and in all the phases of life cycle of a strategic alliance.