Between May 1980 and September 1983, 30 progestin-refractory patients with metastatic endometrial carcinoma were assigned at random to treatment groups receiving either cisplatin (CDDP) 60 mg/m2 every 3 weeks or a combination of cyclophosphamide, doxorubicin, and cisplatin every 4 weeks in doses of 400, 40, and 40 mg/m2, respectively. Those who failed cisplatin were then offered cyclophosphamide 500 mg/m2 plus doxorubicin 40 mg/m2 every 3 weeks. Reduced doses were utilized in both of the combination regimens for patients who had received extensive pelvic radiation. Of the 14 patients initially receiving cisplatin alone, 3 experienced objective tumor regression. One of these three and one other who failed primary cisplatin therapy later responded favorably to cyclophosphamide plus doxorubicin as secondary treatment. Among the 16 patients who took all three drugs simultaneously (CAP) 5 experienced objective partial tumor regression. Survival experience for these relatively late-stage patients has been uniformly poor, with only 7 and 12% surviving at 2 years after beginning CDDP and CAP, respectively. Thus, while cisplatin is clearly an active agent against endometrial carcinoma, its therapeutic index as a single drug or in combination (CAP) is not adequate to preclude new-agent Phase II studies early in patients with advanced disease.