The relationships of 13 potential prognostic factors to objective response to treatment and survival time were investigated, using data gathered on 1,020 patients with advanced stage prostate cancer who have participated in the clinical trials of the National Prostatic Cancer Project. Multivariate statistical analyses revealed that previous hormone response status, analgesics, pain, elevated acid phosphatase, and anemia were the important, independent prognostic factors for objective response to treatment. For survival time, the significant prognostic factors were previous hormone response status, anorexia, elevated acid phosphatase, pain, elevated alkaline phosphatase, obstructive symptoms, tumor grade, performance status, anemia, and age at diagnosis. It is recommended that future treatment protocols for advanced stage prostate cancer take into account heterogeneity of the treatment groups with respect to these factors, either through the design of the protocol, or at the time of analysis.