Abstract :Today, social, economic and technological possibilities are emerging in a dynamic business environment where technological advances bring changing business models, increasing innovation activities, rapid change in consumers' preferences and decreasing product life cycles. Under these circumstances, if companies can bring the right new products to market quickly, they can gain competitive advantage. New product idea selection is an important and difficult step of the innovation process in the software sector. The aim of this study is to determine the factors affecting the choice of new product ideas in software companies. For this purpose, the literature has been systematically reviewed. Then, a list of factors affecting new product idea selection process was generated and revised based on the feedback obtained from academic experts in the field. In order to confirm the validity of the revised list of factors in practice, interviews were conducted with key informants at senior manager level in software companies. As a result, 10 main factors that affect the idea selection process of new products were determined, namely, technical competence, market/marketing analysis, financial management, organizational structure, firm strategy, industrial environment, competitive and similarity analysis, customer analysis, expert appraisal, process management. Also, sub-factors were determined. Keywords : New Product Development, Idea Selection, Software Sector