Medroxyprogesterone acetate (MPA) (1,000 mg daily per os) yielded (mainly subjective) remissions in 8 of 21 patients with hormone-resistant cancer of the prostate. In 24 comparable patients, treated with prednisolone (20 mg daily per os) 3 remissions were observed, indicating a slight superiority of high-dose MPA considering the response rate. The response duration for both drugs was relatively short (2-7 months). No survival benefit for either drug was observed. In patients with hormone-resistant cancer of the prostate, a significant improvement of the performance status should be registrated as subjective response. This is a major aim of any treatment in these patients. Normalization of serum acid phosphatase may also be considered as remission. The type of remission (> 50% reduction of measurable tumor lesions, reduction of serum acid phosphatase, subjective remission) should always be indicated in the individual report dealing with phase II/phase III studies in patients with hormone-resistant prostatic cancer.