To obtain information for published clinical trials in endocrine therapy for cancer in Japan, a computerized literature search of MEDLINE, EMBASE and IGAKU-CHUO-ZASSHI (CD-ROM) was done. We found four articles on randomized trials for prostate cancer and two for breast cancer. In order to obtain information for ongoing randomized phase III trials in endocrine therapy for cancer in the United States and Europe, a search of PDQ (Physician's Data Query) was done. In PDQ, 13 active trials started after January 1990 in endocrine therapy for breast cancer and six active trials started after January 1990 in endocrine therapy for prostate cancer were registered. Out of 13 trials for breast cancer, projected sample sizes were over 1,000 in eight trials, and QOL was selected as an end point in six trials. Out of six trials for prostate cancer, projected sample sizes were over 500 in three trials, and QOL or sexual function was selected as an end point in three trials.