We examined 39 patients with biopsy proven sarcoidosis of the lungs by one-dimensional, two-dimensional and pulsed Doppler echocardiography. In 18 (46.2%) we revealed a prolapse of one or both cusps of the mitral valve which can partly explain some of the complaints and objective findings in these patients (palpitations, chest pain, changes on ECG resembling myocardial infarctions, murmurs, etc.). A minor pericardial effusion was present in 8 (20.5%) of the patients. The finding of reduced systolic thickening and excursions of the interventricular septum in 4 (10.2%) may be related to the frequent prevalence of sarcoid granulomas in the septum. Asymmetric septal hypertrophy, recorded in 4 (10.2%) patients, may have had a similar origin. Administration of corticosteroids did not influence in a significant way any of the echocardiographic indicators nor the amount of pericardial effusion. In patients with palpitations and extrasystolic arrhythmias, however, the extrasystoles disappeared and the patients reported subjective relief in all instances.