We have analyzed the expression of E- and N-cadherins in benign, borderline, and maligant ovarian tumors, and we have correlated the pattern of cadherin expression with the standard clinicopathological parameters. An immunohistochemical technique has been applied to formalin-fixed, paraffin-embedded samples of 20 benign cystic tumors, 20 borderline tumors, and 20 cancers. Expression of E- and N-cadherins immunostaining were compared with the histological type, degree of histological differentiation, International Federation of Gynecology and Obstetrics (FIGO) stage, presence of ascites, occurrence of recurrence, and survival. E-cadherin was homogeneosuly expressed in benign tumors but was heterogeneously expressed or undetectable in most borderline and malignant tumors. In contrast, N-cadherin was detected in most benign and borderline tumors but was absent or heterogeneous in most carcinomas. The difference of expression of E-cadherin and N-cadherin between the three groups of ovarian tumors was statistically significant (respectively, P = .03 and P < .001). In ovarian carcinoma, patients with negative E-cadherin staining present a significantly shorter survival. No correlation was found between cadherin expression and clinicopathological parameters in borderline tumors. Our results suggest that alterations in E-cadherin and N-cadherin expressions are differentially involved in ovarian carcinogenesis and may have diagnostic and prognostic values.