Sustainable development issues in small and medium-sized enterprises (SMEs) are emphasized in the doctoral thesis. The results of author’s investigations highlighted the importance of SMEs for Latvian economy, as well as indicated the low level of productivity demonstrated by this group of Latvian enterprises. This, in turn, points at the problems in measuring and management of an enterprise performance. To solve the problems the concept of sustainable development in combination with the concept of enterprise life cycle are offered for development of a model of sustainable performing of SMEs. Enterprise performances depend on the certain factors and parameters, which vary in different life cycle phases.