The key problem in Latvia-Lithuania cross-border regions is low competitiveness. Research on business growth drivers is an important field of scientific work conducted within the wider regional development studies. Researches in this field would lead to real, tangible benefits for some of the most remote and isolated Latvia-Lithuania cross-border business communities. Today there is no regional business growth potential estimation methodology or disposable recommendations for raising effectiveness of business promotion in Latvia-Lithuania cross-border regions. This project is aimed at developing business growth promotion model and adapting it to the needs of local authorities and businesses. The business growth support software allows simulating the business growth and adjusting financing for different business support measures, as well as to determine effectiveness. It is intended to improve the business environment and entrepreneurship in cross-border regions of Lithuania (Klaip?da and Kaunas counties), Latvia (Kurzeme region) and conterminous regions (cross-border regions). As regards to small and medium sector, its development has important implications for economic development of these regions.