Carboplatin was administered by iv bolus every 28 days to 26 patients who had extensive metastatic or recurrent endometrial adenocarcinoma and no prior chemotherapy exposure. The dose level was 400 mg/m2 in 5 patients with and 4 patients without prior irradiation and 300 mg/m2 in 16 patients with prior pelvic irradiation. Partial disease regressions were seen in 28% of patients (95% confidence interval, 12%-50%), with a median response duration of 129 days. Median survival of all patients was 215 days; median time to disease progression for all patients was 117 days. We conclude that carboplatin is an active agent in advanced endometrial carcinoma and is worthy of further investigation in single-agent and combination chemotherapy.