The incidence of ovarian cancer has been epidemiologically related to female reproductive events and hormone replacement therapy after menopause. This highlights the importance of evaluating the role of sexual steroid hormones in ovarian cancer by the expression of enzymes related to steroid hormone biosynthesis in the tumor cells. This study was aimed to evaluate the presence of 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1), aromatase and estrogen receptor alpha (ERα) in the tumor cells and their association with the overall survival in 111 patients diagnosed with primary ovary tumors. Positive immunoreactivity for HSD17B1 was observed in 74% of the tumors. In the same samples, aromatase and ERα revealed 66% and 47% positivity, respectively. No association was observed of HSD17B1 expression with the histological subtypes and clinical stages of the tumor. The overall survival of patients was improved in HSD17B1 positive group in Kaplan Meier analysis (P = 0.028), and HSD17B1 expression had a protective effect from multivariate proportional regression evaluation (HR=0.44; 95%CI 0.24 – 0.9; P = 0.040). The improved survival was observed in serous epithelial tumors but not in non-serous ovarian tumors. The expression of HSD17B1 in the cells of the serous epithelial ovarian tumors was associated with an improved overall survival. Whereas aromatase and ERα were not related to a better survival. The evaluation of hazard risk factors demonstrated that age and clinical stage displayed worse prognosis, and HSD17B1 expression displayed a protective effect with a better survival outcome in patients of epithelial ovarian tumors.