Our purpose is to demonstrate the relationship between microvessel density (MVD), vascular cuffing (VC), vascular endothelial growth factor (VEGF) expression and clinicopathological parameters in ovarian cancer. Surgical specimens from 105 primary ovarian cancers were examined for vascularization and VEGF expression by immunohistochemical staining. The higher MVD group (MVD> or =70) and the positive VEGF group were associated with better progression-free survival only in early stages. The significant association of the MVD with better progression-free survival was recognized only in the patients with clear cell adenocarcinomas. The complete VC group showed a similar trend as MVD though there was no statistical difference. A multivariate analysis revealed MVD to correlate independently with progression-free survival. In ovarian carcinoma, MVD was found to be an independent prognostic factor. In addition, the higher MVD with clear cell adenocarcinoma had the better prognosis. The clinicopathological role of angiogenesis should be analyzed taking account of histologic type.