Steroid hormone receptors are important determinants of prognosis and predictive behavior in tumor tissues of several origins. Since their role in ovarian cancer is still controversial, we investigated the prevalence and prognostic impact of the estrogen (ER) and progesterone (PR) receptors and combinations (ER+PR+, ER+PR-, ER-PR+, and ER-PR-) in a comparably large number of patients with a long clinical follow-up. The present analysis included 186 patients with invasive ovarian carcinomas treated at the Department of Obstetrics and Gynecology of the Justus-Liebig-University Giessen between 1982 and 1996, the follow-up lasting up to 15.8 years (median 2.4 yrs). The expression of ER and PR was assessed by immunohistochemistry using alkaline phosphatase antialkaline phosphatase in microwave pretreated, formalin fixed, and paraffin embedded specimens of the primary tumors and was evaluated semiquantitatively using a standardized immunoreactive scoring system. Receptor expression and combinations were compared to clinical, histologic and prognostic factors, the tumor proliferation, and the clinical outcome. Kaplan-Meier survival analyses supported the favorable prognostic value of PR and its level of expression in ovarian carcinomas. Especially the ER-PR+ combination, which accounted for 10.2% of all tumors, showed a significantly superior prognosis when compared with all other combinations (survivors 15 of 19 vs. 67 of 167, log rank P = 0.009) and was associated with early stage, low ascites quantity, and higher tumor differentiation. Five-year survival rates were 13/16 (81.3%) for ER-PR+ tumors versus 58/128 (45.3%) for all other steroid hormone receptor combinations. Residual analysis proved the results. The determination of steroid hormone receptor status offers additional prognostic information in ovarian carcinomas. Especially the ER-PR+ phenotype predicts a favorable tumor biology and long term survival, probably reflecting functional effects on tumor proliferation, differentiation, and cellular apoptosis.