We explore how an incumbent firm's internal knowledge and organization structure influences its strategic alliance formation. We propose that the firm's knowledge breadth and the centrality of its R&D organization structure positively influence its absorptive capacity, and consequently, its propensity to form strategic alliances. We also argue that the centrality of the R&D organization structure may be a substitute for the breadth of the knowledge base. We validate our ideas using data on 2647 strategic alliances formed over the period of 1993–2002 by 43 major biopharmaceutical firms in the U.S. and Europe. Our discussion focuses on the application of the knowledge-based view of the firm to strategic alliance research. The implications for public policy in the biopharmaceutical industry are also emphasized.