Survival was evaluated in 455 patients with FIGO stage III invasive ovarian cancer managed between 1983 and 1991. Median follow-up was 73 months. The prognostic significance of clinical and histopathological variables was evaluated. In Cox multivariate analysis, FIGO substage was an independent prognostic factor with a relative hazard (RH) of 1.2 and 1.7 for substage IIIB and IIIC, respectively (P = 0.013). Size of residual disease after surgery was a stronger factor with an RH of 1.2 and 2.4 for residual disease of 0 to 2 cm and more than 2 cm, respectively (P < 0.001). Histologic type had prognostic significance because patients with endometrioid tumors did best, those with mixed, serous, and unclassified tumors had an RH of 1.5 to 1.9, and those with mucinous and clear cell tumors had an RH of 5.4 to 7 (P < 0.001). Grade, ascites, and age had also independent significance. Grade had an RH of 2.5 for grade 2 plus 3 (P < 0.001), ascites had an RH of 1.4 (P 0.018), and age had an RH of 1.7 and 2.4 for age 40 to 70 years and above 70 years, respectively (P < 0.001).