Granulosa cell tumors (GCTs) comprise 2% to 5% of ovarian neoplasms, with unpredictable patterns of recurrence. The HER family, GATA4, and SMAD3 genes are reportedly involved in GCT proliferation and apoptosis and may serve as new predictors of recurrence. The aim of the study was to evaluate novel predictors of recurrence in GCT from a large single institution cohort. Patients diagnosed with GCTs (n=125) between 1975 and 2014 were identified. Clinicopathologic parameters were obtained and immunohistochemical evaluation was performed of calretinin, inhibin, HER2, CD56, SMAD3, and GATA4. Statistical analyses were conducted using Fisher exact test and Kaplan-Meier survival curves and Cox regression analysis. The median follow-up period was 120 months (range, 1-465 mo). Recurrence was noted in 12/125 (9.6%) patients. Kaplan-Meier analysis showed a shorter mean disease-free interval in whites versus blacks (P=0.001), stage III-IV versus stage I-II (P=0.0001), patients treated with surgery+chemotherapy versus surgery (P=0.0001), mitotic rate ≥4 (P=0.005), severe nuclear pleomorphism (P=0.013), high HER2 expression (P=0.001), high CD56 expression (P=0.001), and high SMAD3 expression (P=0.001). On Cox regression analysis, SMAD3 and type of treatment received were the only 2 independent prognostic factors for disease-free interval (P=0.03 and P=0.007, respectively). On subanalysis for early-stage (stage I) GCTs, the need for adjuvant chemotherapy and high expression of SMAD3 continued to be independent predictors of recurrence (HR=10.2, P=0.01 and HR=8.9, P=0.001, respectively).