This study assumes that firms with significant increases in research and development (R&D) expenditures have more information asymmetry between managers and investors. These firms may have greater difficulty in reflecting intrinsic firm value than other firms, and may have incentive to repurchase outstanding shares. Consequently, this study examines the relations among R&D, abnormal stock returns, and share repurchases. The empirical results demonstrate that firms that economically significantly increase in R&D exhibit abnormal stock returns. Such firms are more likely to make share repurchases, and abnormal stock returns are associated with positive repurchase announcements.