Mutations in the beta-catenin gene are common in ovarian endometrioid carcinoma. Few studies have addressed the association of beta-catenin expression with tumor characteristics and patient outcome, yielding controversial results. The purpose of this study was to retrospectively assess the expression of beta-catenin in ovarian endometrioid carcinoma and correlate its expression with the Gynecologic Oncology Group's (GOG) grading system, clinicopathological characteristics, and patient survival. A total of 49 patients with primary ovarian endometrioid carcinoma were included in this study. A four-tier score grading system was used for the membranous staining (negative, weak, moderate, and strong) and the percentage of positive cells for the nuclear staining of beta-catenin. The status of five morphometric parameters, nuclear morphology (uniform or pleomorphic), mitotic count, glandular pattern, degree of squamous differentiation, and status of papillary pattern, was assessed. We found that a low membranous expression of beta-catenin and a high mitotic count (>15 per 10 high-power fields) were significantly associated with poor prognosis and early recurrence of ovarian endometrioid carcinoma. In addition, cases with nuclear expression of beta-catenin showed an intermediate overall survival risk and late disease recurrence. Young age at the time of diagnosis, advanced disease stage, and suboptimal debulking were among the clinical factors predicting poor survival and early disease recurrence. The presence of squamous differentiation, a papillary pattern or nuclear pleomorphism did not show any correlation with overall survival or disease-free survival. Low membranous expression of beta-catenin and high mitotic count are poor prognostic indicators in patients with ovarian endometrioid carcinoma, whereas the GOG grading system showed no prognostic value. Our data suggest that there is a need to define a better grading system for ovarian endometrioid carcinoma. Molecular markers such as beta-catenin and mitotic count could aid in defining this grading system.