Two cases of Wegener's granulomatosis occurred in two women aged 53 and 67 years. The clinical course in both was of rapid deterioration resulting from renal failure and leading to death. At necropsy both cases showed severe and disseminated necrotising granulomatosis in the lungs, kidneys, and spleen but with variable degrees of cardiac and systemic vasculitis. One patient, with appreciable cardiac damage, developed a P wave abnormality due to atrial disease. In patients with Wegener's granulomatosis damage to the heart should be suspected and signs of conduction system abnormalities looked for on the electrocardiogram.