Twenty-three patients with advanced or recurrent endometrial carcinoma no longer amenable to control with surgery and/or radiotherapy were entered into study. Twenty-two actually received therapy with piperazinedione at a dose of 9 mg/m2 intravenously every 3 weeks. One partial responder was observed. Adverse effects were primarily manifested as myelosuppression, and were significant but tolerable. Due to the low order of activity observed, this drug is not recommended for further study in the treatment of endometrial carcinoma.