Nitroglycerin plasters were applied to the penis in 10 impotent men and the erectile effect assessed. During laboratory testing all patients achieved an erectile response. Self-administration of nitroglycerin patches restored potency in 4 patients and was preferred to papaverine auto-injection by 3. Headache was a common side effect during initial administration. An attempt to treat impotence with nitroglycerin plaster seems worthwhile before starting extensive investigations or invasive treatment.