The purpose of this study was to determine the influence of tumor grade, distribution, and extent of carcinomatosis in minimal residual epithelial ovarian cancer after primary optimal cytoreductive surgery. Between 1978 and 1990, 112 patients with stage III epithelial ovarian cancer underwent primary cytoreductive surgery and had minimal residual disease, i.e., < 5 mm maximum diameter of residual tumor nodules. Seventy-eight patients (70%) had operative reports that contained sufficient detail to be included in this study. We retrospectively reviewed histopathological reports to determine tumor grade, operative and clinical notes to determine one predominant distribution pattern of residual metastases (pelvic/omental, diaphragmatic, or intestinal/mesenteric), and the approximate extent of residual disease (no gross disease, scattered nodules, or extensive carcinomatosis). Standard actuarial survival analysis was performed, and the log-rank chi 2 was used. At the mean follow-up time of 24.4 months, survival was 65% for grade 2 or 3 disease versus 93% for grade 1 (log-rank P < 0.01). Survival was 66% for residual disease in the intestines/mesentery versus 70 and 81% for residual disease in the diaphragm and pelvis/omentum, respectively (log-rank P < 0.03). Survival was 48% for residual extensive carcinomatosis versus 76 and 93% for minimal residual nodules and no gross residual, respectively (log-rank P < 0.001). In conclusion, in women who have minimal residual ovarian cancer after primary cytoreductive surgery, tumor grade and the distribution and extent of carcinomatosis can independently affect survival. The shortest survival correlated with high-grade tumor and extensive carcinomatosis predominantly involving the intestines and mesentery.