An open randomised Phase III trial was conducted of the depot GnRH analogue goserelin (Zoladex) versus stilboestrol (3 mg/day) in patients with advanced or metastatic prostate cancer. The study included 250 patients and the median follow-up was 43 months. In the Zoladex arm the time to first response was achieved earlier and more patients reported an improvement in symptoms. There was no statistically significant difference between the Zoladex and the stilboestrol arms with regard to survival and time to treatment failure. A major reason for treatment failure was the preponderance of adverse events in patients receiving stilboestrol. It is suggested that stilboestrol should no longer be used for prostate cancer when equally effective alternative treatments are available.