Abstract: Objective 　To investigate the expression of cyclooxygenase-2 (COX-2) in endome-trial carcinoma and its relationship to angiogenesis. Methods 　The expression of COX-2 and vascular endothelial growth factor (VEGF) in 34 cases of endometrial carcinoma was evaluated by immunohistochemistry SP staining. Microvessel density (MVD) of endomet rial carcinoma was also determined with anti-CD34 as the label. Results 　The expression late of COX-2 in 34 cases was 64. 7 % but not in cont rol endomet rium. The level of COX-2 expression was higher in grade Ⅱtumor than in grade Ⅲ tumor ( P < 0. 05) . MVD was (41. 53 ±19. 10) and (28. 79 ±8. 20) in endomet rium carcinoma positive and negative for COX-2 ( P< 0. 05) . The expression of COX-2 was positively correlated with expression of VEGF and MVD ( P <0. 01 ; P < 0. 0001, respectively ) . Conclusion 　COX-2 may involve early in endomet rium neoplastic progression. The expression of COX-2 in endomet rial carcinoma may induce the expression of VEGF, increase angiogenesis and enhance tumor growth and invasion.