Our objective was to investigate recurrence patterns and conduct an outcome analysis of patients with endometrial stromal sarcoma (ESS).A retrospective review yielded 30 patients with ESS (20 low-grade, 10 high-grade) who underwent primary surgical resection from 1982 to 2005. Median follow-up was 42 months.All patients underwent hysterectomy, whereas pelvic (P) and paraaortic (PA) lymphadenectomy were performed in 12 and 7 patients, respectively. A median of 26 pelvic lymph nodes and 9 PA lymph nodes were removed. Pelvic or PA lymphatic disease was noted in 25% and 29% of patients, respectively. Extrauterine disease was identified in 11 (45%) of 24 patients undergoing exploratory laparotomy; 6 had no residual disease after cytoreductive surgery. None of these 6 patients experienced abdominal failure, but 1 had a hematological recurrence. Thrombotic complications were noted in 13% of patients. The 5-year overall survival was 65%. Overall survival was influenced by grade (79% vs 40%, P = 0.03) and extrauterine disease (77% vs 32%, P = 0.01). No patient who underwent a systematic lymphadenectomy had a lymphatic recurrence, irrespective of nodal status. There were 7 (23%) hematological recurrences; 2 in surgical stage I ESS. Two patients with low-grade ESS remain without evidence of disease 130 and 210 months after secondary cytoreduction. In contrast, no patient with high-grade ESS survived a recurrence.There is high prevalence of extrauterine and nodal disease in ESS. Patients are at high risk for thrombotic complications. If aggressively staged, the predominant failure risk for stage I patients is hematogenous, suggesting the need for improved systemic treatments.