Two patients with pulmonary metastases from a prostatic carcinoma are described. When first seen by the pulmonary physician, respiratory symptoms were predominant and diagnosis of the primary site was not yet made. Orchidectomy achieved an impressive response with regression of symptoms and radiological lesions within weeks. Since metastatic deposits from prostatic origin may respond promptly to endocrine manipulation, this possibility must be taken into account in the evaluation of any patient with pulmonary metastases of unknown origin.