Ketoconazole has been used with success to treat disseminated intravascular coagulation and acute spinal cord compression syndromes associated with metastatic prostatic adenocarcinoma. It effects prompt, reversible medical castration, making it especially useful as empiric therapy when histologic diagnosis is delayed but prostate cancer is suspected. Side effects are usually limited to asthenia, nausea, diarrhea, and gynecomastia, but a theoretical risk of adrenal suppression exists. We report a case of fulminant adrenal crisis precipitated by ketoconazole given on a 6-hour dosing schedule in a patient with nerve root compression secondary to prostatic metastases. Through a review of the literature, we attempt to provide a better understanding of the use and potential dangers associated with ketoconazole therapy.