This retrospective study of ovarian cancer aimed to elucidate whether expression of apoptosis-related proteins, bcl-2, p53 or MDM-2, is associated with resistance to chemotherapy, especially cisplatin (CDDP) based chemotherapy. Expression of bcl-2, p53 and MDM-2 was assessed by immunohistochemical staining of tumour tissues collected at initial surgery prior to treatment with CDDP-based chemotherapy. Among 66 patients with advanced ovarian cancer with measurable tumour following surgery and evaluable for response to chemotherapy, 42, 45 and 56% were positive for bcl-2, p53 and MDM-2, respectively. Significantly fewer tumours of patients who had a complete response to chemotherapy (CR) showed positivity for bcl-2 (2/20) than for p53 (6/20) and MDM-2 (8/20, P < 0.001). There was an inverse correlation between bcl-2 staining and initial response to chemotherapy, especially in serous and endometrial adenocarcinomas. In patients with stage III-IV, serous or endometrioid adenocarcinomas, significantly poorer survival was seen for those with bcl-2 positive tumours than those with negative bcl-2 staining (P = 0.0064). p53 and MDM-2 were not correlated with initial response to chemotherapy. Multivariate analysis revealed that bcl-2, residual tumour size and histology were significant independent prognostic factors. These results suggest that bcl-2 can be a possible predictor of response to chemotherapy and prognosis in patients with advanced ovarian carcinoma.