The first cytological study examining the expression of P53, BCL2 and MIB 1 expressions in correlation with other clinicopathological parameters in ascitic fluids of patients with serous ovarian carcinomas.Fifty women 35-75 years old were diagnosed cytologically and confirmed histologically after operation in the University Hospital of Crete. All carcinomas were serous type and eight(8) of grade I, eighteen (18) of grade II and twenty two (22) of grade III. All carcinomas were staged according to the Figo criteria. Fifteen (15) were of Figo stage III and thirty five (35) were of Figo stage IV. For p53 and bcl-2, staining was evaluated on a semiquantitative scale depending on the number of cells showing positivity. For MIB1, the percentage of positive nuclei was calculated. Main outcome measure(s): The expression of P53, BCL2 and MIB 1 (Ki 67) correlated with tumor grade and Figo stages were estimated by chi-square (χ2).The expression of P53 and MIB1 were found to be statistically significant (p < 0.005) correlated with Figo stage and tumor grade. A statistical significant correlation was also found between BCL2 expression and tumor Grade ( p < 0.005) but not between BCL2 expression and Figo Stage. The study found a high expression of P53 (64%) and MIB1 (72%) and an expression of BCL2 (48%) in ascitic fluid of patients with ovarian carcinoma. A statistically significant correlation between P53 and MIB1 expression correlated with tumor grade and Figo stage (p < 0.005) and a statistically significant correlation between BCL2 expression and tumor grade but no with the Figo stage was found (p < 0.005). There was a positive correlation between P53 and MIB1. No significant association was found between P53 and BCL2 expression or MIB1 labeling index.Our data show significant differences in the expression of these markers in ovarian tumors and suggest a possible role for these tumor-associated genes as supplemental tools in prognosis and further definition of the biologic potential of these tumors.