The prognostic value of the volume-weighted mean nuclear volume (MNV) was investigated retrospectively in 100 ovarian cancer patients with FIGO-stage IB–II (n= 51) and stage III–IV (n= 49) serous tumors. No association was demonstrated between the MNV and the survival or between the MNV and two of five additional parameters: age and amount of residual tumor. However, both in stage IB–II and stage III–IV carcinomas, the MNV increased significantly with increasing tumor grade and DNA-index. Furthermore, FIGO-stage IB–II patients had significantly smaller nuclei than patients with stage III–IV disease.