Background Ovarian sex cord-stromal tumors (SCSTs) are relatively rare tumor. The standard treatment is surgery, while adjuvant chemotherapy remains controversial. This study evaluated the effect of adjuvant chemotherapy and disease-specific survival (DSS) in patients with SCSTs.Methods 323 Patients with SCSTs were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database. Demographic and clinicopathological characteristics were compared using Mann–Whitney U-test, Fisher’s exact test, and chi-square test. DSS were estimated by Kaplan–Meier and compared with the log-rank test. Cox proportional hazards model was used to control for confounders.Results A total of 323 patients were included in this study, and the mean age was 44 years (range, 10-89 years). The most common histologic subtype was granulosa cell tumor (GCT) (n=197, 61%). 60.7% were diagnosed with stage IA or IB disease and 18% with stage IC disease. Among them, 62.2% of patients (n=201) received chemotherapy. The Median follow-up time was 71 months (range,1-224 months). 12.7% (41/323) of patients experienced death. Patients who did not received chemotherapy (n=122) had better DSS compared to those who received chemotherapy, 5-year DSS rates were 93.5% VS 80.3% (P = 0.0005), 10-year DSS rates were 93.0% and 78.69% (P = 0.0002). Multiple Cox regression analysis showed that higher stage (p<0.001), poor differentiation(P=0.24), larger tumor size(size>10cm) (P=0.018) were independently associated with an increased hazard of death,while histological subtype(P=0.082),adjuvant chemotherapy(p=0.762), complete staging surgery(p=0.554)was not associated with prognosis.ConclusionChemotherapy could not improve the prognosis and may be associated with poorer DSS. Age, histopathologic subtype, complete staging surgery, lymphadenectomy are not associated with prognosis.