In this review, the cardiac lesions which develop in association with the various collagen-vascular diseases are described. In rheumatoid arthritis, the most frequent lesions are: fibrous obliterative pericarditis, with pericardial deposits of calcium, fibrin, cholesterol, and rheumatoid granulomas; granulomatous or nonspecific myocarditis; valvulitis, vasculitis, and amyloid deposits. In ankylosing spondylitis, the lesions involve mainly the valves (aortic and mitral valves) and the aorta. In systemic lupus erythematosus, the predominant cardiovascular lesions are: pericarditis, Libman-Sacks endocarditis, nonspecific myocarditis, vasculitis with fibrinoid necrosis, and acceleration of atherosclerosis. In scleroderma, the main cardiac lesion is fibrosis with only scanty inflammatory cells; pericarditis and nonbacterial thrombotic endocarditis also occur. In dermatomyositis/polymyositis, fibrous or fibrinous pericarditis can occur, as well as myocarditis with infiltrates of lymphocytes and plasma cells and with degeneration and necrosis of myocytes; valvulitis is uncommon except when the disease is related to mucinous adenocarcinoma. In polyarteritis nodosa, various stages of necrotizing vasculitis involve all layers of the arterial walls; foci of myocardial necrosis of various sizes can occur in association with these lesions; cardiac hypertrophy related to hypertension and pericarditis related to uremia, may also be found. In Wegener's granulomatosis, pericarditis, inflammatory infiltrates, necrotizing granulomas, and vasculitis have been observed in the heart.