Ketoconazole high dose (H.D.) effectively reduces the testosterone production in both adrenals and testes. Its use in the management of (metastatic) prostate cancer has been advocated. Even in relapsing patients, after previous hormonal therapy, ketoconazole H.D. could be of value. Twenty-eight relapsing patients, of whom 15 were evaluable at three months, have been treated with ketoconazole H.D. As could be expected, objective response was seen in only a small number of patients followed up till nine months. Subjective improvement, however, was noticed in the majority of symptomatic patients. The side effects and toxicity of the therapy remain a major limitation for the use of ketoconazole, be it as first line treatment or as therapy for relapsing patients.