M-mode echocardiographic findings are described in 21 patients with endomyocardial fibrosis. Features associated with right ventricular endomyocardial fibrosis include: (i) exaggerated motion and thickening of the anterior right ventricular wall; (ii) increased right ventricular end-diastolic dimension; and (iii) paradoxical septal motion. Pericardial effusion (viz an echo-free space behind the posterior left ventricular wall) was shown in three patients. The tricuspid valve was easily recorded in all. Six patients with left ventricular endomyocardial fibrosis had diminished left ventricular end-diastolic dimension. Three had echo features of pulmonary hypertension (viz reduced e-f slope, absent a wave in sinus rhythm, and systolic notching of the pulmonary valve echogram). Fine fluttering of the anterior mitral valve and tricuspid valve echo was observed in two patients (one of whom was in sinus rhythm) with biventricular endomyocardial fibrosis, and no angiographic evidence of aortic regurgitation.