Prior studies of the risk of recurrence following negative second-look laparotomy have included patients treated with a variety of chemotherapeutic regimens, including nonplatinum regimens. We have examined the long-term outcome and risk factors for recurrence among a homogeneous group of platinum-treated patients. During the years 1978-1987, 91 patients at Memorial Sloan-Kettering Cancer Center had a negative second-look laparotomy following platinum-based chemotherapy for epithelial ovarian cancer. The mean age at diagnosis was 57 years, with a range of 30 to 79. Distribution by stage was as follows: I, 10; II, 18; III, 57; IV, 6. The mean number of cycles of platinum prior to second-look surgery was 6.3. The mean number of biopsies taken at negative second-look laparotomy was 12. Lymph node biopsies were done in 47/91 (52%) of patients. Median follow-up from the date of second-look laparotomy was 54.6 months among survivors. Forty of ninety-one patients (44%) have had recurrence, almost 40% of which were outside the peritoneal cavity. The mean interval from negative second-look laparotomy to recurrence was 24 months (range, 2-70 months). By multivariate analysis the risk of recurrence was significantly related to stage (P = 0.017), histologic grade (P = 0.041), and the amount of tumor remaining after the first operation for ovarian cancer (P = 0.015). Recurrence by stage was as follows: stage I, 1/10 (10%); stage II, 5/18 (28%); stage III, 31/57 (54%); stage IV, 3/6 (50%). Recurrence by grade was as follows: grade 1, 4/18 (22%); grade 2, 11/28 (39%); grade 3, 25/45 (56%). There was no relationship between the risk of recurrence and the number of cycles of platinum, the number of biopsies performed at second-look, or the number of months from primary surgery to second-look. Patients having negative second-look laparotomy following platinum-based chemotherapy for advanced epithelial ovarian cancer have a substantial risk of recurrence, particularly within the first 3 years. Such patients should be offered participation in clinical trials of consolidation therapy directed against both intraperitoneal and extraperitoneal disease.