In the biotechnology sector small R&D intensive firms play a fundamental role to keep innovation rates high. With less bureaucratic burdens, low level of hierarchy and high internal flexibility they are able to move fast and to make most efficient use of unique competences. Still their shortage in resources, related to company size, makes them dependent on a strong network of alliances to get access to missing competences and materials. This paper aims at establishing the influence of alliance characteristics on the innovation performance of firms in the biotechnology sector. It presents a conceptual model to clarify the special role of collaboration intensity and how human resource exchange is related to innovation performance of biotechnology alliances.