OBJECTIVE To determine the efficacy of three courses of intraperitoneal (i.p.) cisplatin (CDDP) and etoposide (VP-16) as consolidation therapy following pathologically negative second-look surgical reassessment for Stage IIC-IV epithelial ovarian cancer (EOC). METHODS Between September 1988 and April 1996, 40 patients were treated with three cycles of i.p. CDDP (100 mg/m2)/VP-16 (200 mg/m2) as consolidation therapy. Survival was compared to that of a group of 46 contemporaneous patients undergoing observation only. RESULTS Median age of the 36 eligible patients was 52 years (range 30-70 years). Stage distribution was II (3), III (31), and IV (2); histologic grade was 1 (2), 2 (7), 3 (25), and not recorded (2); and residual disease at completion of initial surgery was none/microscopic in 13/36 (36%) patients. Median age of the 46 patients who did not receive consolidation was 52 years (range, 27-80 years); stage distribution was II (18), III (26), and IV (2); histologic grade was 1 (5), 2 (12), 3 (28), and not recorded (1). With a median follow-up of 36 months in both groups, 14/36 (39%) of the protocol group have recurred compared with 25/46 (54%) of those undergoing observation alone. Median disease-free survival (DFS) for the observed patients is 28.5 months and has not been reached in the consolidation group. Disease-free survival distribution between the two groups was compared using the log-rank test and was found to be significant (P = 0.03). Multivariate analysis revealed that the only significant predictor of improved DFS was protocol treatment (P < 0.01). CONCLUSIONS Intraperitoneal consolidation with CDDP/VP-16 following negative second-look reassessment in patients with advanced EOC resulted in a significant increase in DFS compared to nonprotocol patients treated concurrently who underwent observation alone.