15010 Background: To determine if extent of lymphadenectomy affects the disease-specific survival of women with advanced-stage ovarian cancer. Methods: Demographic and clinico-pathologic information were obtained from the Surveillance, Epidemiology and End Results Program from 1988–2001 and analyzed using Kaplan-Meier methods and Cox proportional hazards regression. Results: Of the 15,320 women with stage IIIB-IV disease, 763 (5.0%) had stage IIIB, 5,266 (34.4%) stage IIIC, and 9,291 (60.7%) had stage IV disease. The median age was 66 (range: 1–101). 13,251 (86.5%) were White, 1,049 (6.9%) Black, 716 (4.7%) Asian, and 304 (1.9%) were Other. Of the patients who underwent a lymphadenectomy, the median number of nodes resected was 6 (range: 1–90). We divided our study group 3 groups based on the extent of lymphadenectomy (0, <10, 10–20, and >20). In the overall study group, the extent of lymphadenectomy improved the survival from 21.1%, 40.5%, 45.1% to 46.0%, respectively (p < 0.001). Patients with stage IIIB, IIIC, and IV disease had an improvement in survival associated with lymphadenectomy (see table ). In patients with non-clear cell epithelial carcinoma, the extent of lymphadenectomy was associated with improved survivals 20.9%, 39.8%, 45.4%, and 45.9%, respectively (p < 0.0001). Moreover, those with clear cell cancers (p = 0.0001), germ cell (p = 0.001) and sarcomas of the ovary (p = 0.02) also had a survival benefit; however no benefit was demonstrated in sex cord stromal tumors (p = 0.99). In multivariate analysis, a more extensive lymphadenectomy remained significant as an independent prognostic factor for improved survival after adjusting for all other independent prognostic factors including age, year of diagnosis, surgery, histology, stage, and grade. Conclusions: Our findings suggest that the extent of lymphadenectomy improves the disease-specific survival of women with stage IIIB-IV ovarian cancer. This benefit was demonstrated in epithelial, germ cell, and sarcomas of the ovary. [Table: see text] No significant financial relationships to disclose.