Previous studies have suggested that overexpression of c-erbB-2 oncogene occurs in 15~40% of breast cancers and that overexpression is associated with poor survival. In the present study, we have usedan immunohistochemical technique involving a polyclonal antibody specifically reactive with external domain of c-earB-e to study expression of c-erbB-2 in paraffin embedded sections of normal ovary(5) and epithelial ovarian cancer(42). The intensity of staining for c-erbB-2 was always moderate or less ( 0~2+) in normal ovarian epithelium. Among 42 ovarian cancers, 31 (77.8%) had staining similar to that for mormal ovarian epithelium (0~2+) while 11 (26.25) stained heavily (3+). Survival of the 11 patients with high c-erbB-2 expression was significantly worse than that of the 31 patients with normal c-erbB-2 expression. ( 5-year survival : 81% vs 45% ( p=0.0491), median survival: 34 vs 43 months ( [=0.0485)) In addition, patients whose tumors had high c-erbB-2 expression were significantly less likely to have a complete response to primary therapy or have a negative second look laparotomy. These findings suggest that overexpression of c-erbB-2 oncoprotein may be associated with poor survival in epithelial ovarian cancer and c-erbB-2 deserves further evaluation as a prognostic marker in epithelial ovarian cancer.