Thirty-four patients with advanced cancer of various origins and documented disease progression were treated with continuous daily doses of 50-150 mg of oral trofosfamide (TRO). Of 31 evaluable patients, 5 responded to this treatment (1 complete remission and 4 partial remissions) and 12 patients had stable disease. Four of 9 patients with advanced ovarian cancer resistant to platinum-containing regimens and paclitaxel responded to oral TRO. The median treatment duration was 26 weeks for responders and 6 weeks for nonresponders, with cumulative doses of up to 46.000 mg TRO. Response duration was 11-47 weeks. No significant side effects were observed. Oral TRO given in the outpatient setting seems to be an attractive therapeutic option for heavily pretreated cancer patients, and it has remarkable antitumor effects in patients with ovarian cancer.