Much evidence suggests that an inflammatory condition provides a microenvironment favorable for tumor growth. One of the main components in the healing wound is the induction of cyclooxygenase-2 (COX-2) and prostaglandins, and many solid tumors have been known to overexpress COX-2. The present study investigated the relationship between surgical wounds and tumor growth and the roles of COX-2 and inflammatory reaction in this microenvironment. We created surgical wounds in syngeneic mice for the implantation of SCC VII murine cancer cell line. Accelerated tumor growth and increased angiogenesis by surgical wounds were clearly observed in C3H/HeJ mice with SCC VII tumor. The COX-2 expression of peritumoral tissues and leukocyte infiltration partly explained the accelerated tumor growth, especially in the early phase after surgical wounding. Celecoxib had a significantly suppressive effect on tumor growth, angiogenesis, and metastasis in tumor-implanted mice with surgical wounds. This tumor-suppressive action of celecoxib did not show any noticeable side effects on the late wound healing and on the gastrointestinal tracts. Prophylactic use of the drug can be advocated in many clinical situations, such as residual tumors or contamination of surgical fields by tumor cells.