Prognosis and biologic behavior of malignant ovarian tumors have been assessed by clinical staging, morphological grading and many other variables. Recently DNA ploidy measured by flow cytometry has been suggested as an additional important indicator of the tumor behavior and prognosis. The author measured DNA ploidy, S-phase fraction and DNA Index in 36 patients of epithelial ovarian tumors(17 were malignant, and 19 were borderline) by flow cytometric analysis of paraffin embedded tumor blocks. Comparing with FIGO stage, tumor grade, histologic type and others, the author investigated the clinical significance of the results of flow cytometric analysis. The results obtained as follows : (continue)