The authors report 3 cases of acromegaly diagnosed while the patients were in hospital for cardiovascular disease: arterial hypertension in two and hypertrophic myocardiopathy in all three. Coronary arteriography was normal in the 3 patients. The exercise-induced dyspnoea observed in these 3 cases was unexplained by right and left cardiac catheterization results (normal pressures, normal or increased cardiac index). It was most probably related to the myocardial hypertrophy and to abnormalities in diastolic function demonstrated by radioisotopic methods in patients 2 and 3. The degree of myocardial hypertrophy present in these 3 patients seemed to correlate with the size of the pituitary adenoma and the plasma level of growth hormone rather than with the duration or degree of arterial hypertension. After excision of the pituitary adenoma hypertension persisted in 1 case, due to associated adrenal gland hyperplasia, and subsided in the other cases. Abnormalities of diastolic function and dyspnoea are gradually regressing but left ventricular hypertrophy has not significantly decreased after 6 post-operative months.