A 14-year-old boy developed severe respiratory failure during the course of acute rheumatic fever. The results of all microbiological studies were normal. Rheumatic carditis or left ventricular failure was excluded by routine examinations, catheterization of the right side of the heart, and multiple-gated radionuclide ventriculography. The patient recovered completely after a course of high-dose prednisone. To our knowledge, this is the first well-documented case of rheumatic pneumonia in which the lung disease could be attributed to the rheumatic disease and not to a pathologic heart condition.