The present study was designed to investigate whether cyclooxygenase (COX) inhibitors (coxibs) could prolong survival time by attenuating the tumor growth of ovarian cancer xenograft-bearing mice. Tumor growth and survival time were observed and compared in mice which were treated with a COX-1 inhibitor (SC-560) and a COX-2 inhibitor (celecoxib) every other day for a 21 day period from the day of tumor formation. The trial lasted a total of 121 days. The combination therapy resulted in statistically significant inhibition of tumor size compared with the control group (P<0.05). Additionally, single treatment of SC-560 or celecoxib significantly prolonged the mean survival time of mice compared with the control group (P<0.05). We suggest that COX-1 and COX-2 inhibitors may improve survival and inhibit tumor growth, and that the tumor growth inhibition by coxibs may be the contributing factor for the prolonged survival time in mouse xenograft models.