The aim of the current study is to investigate the clinical and molecular factors associated with cytoreduction among women with advanced stage epithelial ovarian carcinoma EOC. Sev enty two women with FIGO stage III and IV EOC or primary peritoneal carcinoma (PPC) underwent similar attempt at surgical cytoreduction, mostly by the same surgeon. The histologic material of these patients was reviewed and the histologic subtype and grade were assigned. Immunohistochemical tests were performed for expression of molecular regulators of apoptosis (p53, p21, Bcl2,Bclx, Bax) and chemoresistance (PGP, MRP, LRP, GST). The following factors were assessed for their association with complete (no residual tumor) and optimal (residual tumor < 1 cm) cytoreduction: type of carcinoma (EOC versus PPC), stage, CA- 125 values, ascites, histology, tumor grade, and p53, p21, Bcl2,Bcl x, Bax, PGP,MRP,LRP,GST expression using the odds ratio and associated 95% confidence intervals. Significant univariate odds ratios were assessed jointly in a multivariate logistic regression model. Receiver operating characteristic curve analysis was performed to determine the CA- 125 level with the maximal cytoreduction prognostic power. Twenty three (31.9% ) women had no residual tumor, 35 (48.6% ) had ≤ 1 cm residual tumor and 14 (19.4% ) had residual tumor >1cm. Factors with significant univariate associations with complete cytoreduction included stage, CA- 125 level, ascites, histology, and p53. p53 expression was the only factor which remained significant in the multivariate analysis (odds ratio 7.2, 95% CI 1.5, 34.9). A preoperative CA- 125 value of ≤ 500 IU/ml best determined complete cytoreducibility. Innate tumor characteristics determine cytoreducibility of women with ovarian carcinoma. Pre operative evaluation of p53 expression may be of value in predicting the outcome of cytoreductive surgery in women with advanced stage EOC. The aim of the current study is to investigate the clinical and molecular factors associated with cytoreduction among women with advanced stage epithelial ovarian carcinoma EOC. Sev enty two women with FIGO stage III and IV EOC or primary peritoneal carcinoma (PPC) underwent similar attempt at surgical The histologic material of these patients was reviewed and the histologic subtype and grade were assigned. Immunohistochemical tests were performed for expression of molecular regulators of apoptosis (p53, p21, Bcl2, Bclx, Bax) and chemoresistance PGP, MRP, LRP, GST). The following factors were assessed for their association with complete (no residual tumor) and optimal (residual tumor <1 cm) cytoreduction: type of carcinoma (EOC versus PPC) , ascites, histology, tumor grade, and p53, p21, Bcl2, Bcl x, Bax, PGP, MRP, LRP, GST expression using the odds ratio and associated 95% confidence intervals. Significant univariate o dds ratios were distributed jointly in a multivariate logistic regression model. Receiver operating characteristic curve analysis was performed to determine the CA- 125 level with the maximal cytoreduction prognostic power. Twenty three (31.9%) women had no residual tumor, 35 (48.6%) had ≤ 1 cm residual tumor and 14 (19.4%) had residual tumor> 1 cm. Factors with significant univariate associations with complete cytoreduction included stage, CA-125 level, ascites, histology, and p53. Innate tumor characteristics determine cytoreducibility of women with ovarian carcinoma. Preoperative evaluation of p53 (odds ratio 7.2, 95% CI 1.5, 34.9). A preoperative CA- 125 value of ≤ 500 IU / ml best determined complete cytoreducibility. expression may be of value in predicting the outcome of cytoreductive surgery in women with advanced stage EOC.