The relationship between erectile dysfunction and sulpiride stimulatory effect on prolactin secretion was studied in 13 married male psychiatric outpatients. The patients population was comprised of 2 groups: patients with anxiety disorders resistant to minor tranquilizers who were treated with sulpiride up to 200 mg/day, and schizophrenic patients treated with sulpiride 600 mg/day. All the patients were maintained on maximal dose for a period of 3 weeks. Sexual function and blood prolactin levels were monitored once weekly. The patients who developed impotence were maintained on higher doses of sulpiride and exhibited higher prolactin levels in comparison to the potent patients. Restoration of potency was observed after reduction or discontinuation of sulpiride treatment. It is concluded that sulpiride induced impotence is associated with hyperprolactinemia.