Chronic pericarditis was the most common rheumatoid lesion of the heart in 47 autopsied patients with seropositive rheumatoid arthritis; it was uncommon in an equal number of matched controls. This lesion, almost always benign, is often associated with electrocardiogram changes, long duration of arthritis, and severe musculoskeletal disability, and rarely with constrictive pericarditis. Myocarditis and rheumatoid granulomas are less frequent but also characteristic. Myocarditis was found more frequently in patients with severe osteoporosis. Whether rheumatoid coronary arteritis is a clinically significant entity remains unsettled. Functionally important valvular disease is rare, though cases of granulomatous valvulitis and valvular insufficiency are documented. Nonspecific endocarditis is frequent, but not more so than in a control population. Most, but not all, heart disease related to rheumatoid arthritis is innocuous.