Sixty-two patients with advanced ovarian adenocarcinoma (stages III and IV) and without prior chemotherapy or radiotherapy were treated with a four-drug combination consisting of cyclophosphamide, hexamethylmelamine, 5-fluorouracil (5-FU), and cisplatin (Chex-UP). All patients were evaluable for toxicity and response, and survivors have been observed for a minimum of 48 months. The overall response rate to Chex-UP chemotherapy was 69%, with 12 patients (19%) achieving a pathologically confirmed complete remission (CR) as documented by a negative second-look laparotomy. Seven of the twelve patients (58%) who achieved a surgically confirmed CR were randomized to six cycles of intraperitoneal (IP) 5-FU. There have been seven relapses in patients who had a negative second-look laparotomy, but only four of the patients died from recurrent ovarian cancer. The median duration of remission following a negative second-look laparotomy was 53 months, while the median duration of survival has not been reached and will exceed 7.5 years. Seventeen patients (27%) achieved a clinical CR with chemotherapy but were found to have residual disease at second-look laparotomy. The median survival for these patients was 29 months, which was statistically inferior to that achieved for those patients with a negative second-look laparotomy (P less than .002), and only one patient is alive after 4 years. All patients who either achieved a partial response (PR) to therapy (14 of 62; 23%) or did not respond to therapy (19 of 62; 31%) died of ovarian cancer by 24 months. Thus, prolonged survival is associated with a surgically confirmed CR to induction therapy with Chex-UP. However, only a minority of advanced-stage ovarian cancer patients (15%) are alive 4 years after initiation of treatment with this regimen.