Abstract One hundred ten patients with metastatic prostate cancer (Stage D 2) were analyzed to determine the associations among time until progression and the pretreatment testosterone level, extent of bone metastases as indicated by a semiquantitative grading scale for extent of disease, performance status, race, age, and the pretreatment level of prostatic acid phosphatase (PAP). The median follow-up period was twenty-one months, with a range of four to eighty-nine months. All patients received androgen deprivation at the time metastases were identified. A multivariate analysis demonstrated that pretreatment serum testosterone was the most significant variable associated with time until progression ( P < 0.01) and that the extent of bone metastases observed on the bone scan was the second most important variable ( P < 0.05). The following factors did not significantly correlate with progression free intervals: age, race, and PAP. The performance status was significantly correlated, but was nonsignificant in the multivariate analysis when the model already included the testosterone level and the extent of bone metastases. Patients with a pretreatment testosterone level of less than 300 ng/dL and with more than six areas of increased uptake on the bone scan progressed more rapidly.