We have studied the cardiac manifestations of connective tissue diseases. In 213 files of patients with connective tissue disease of the Department of Medicina I, Hospital Santa Maria, during 21 years. Cardiac manifestations were observed in 63 (90%) SLE. Pericarditis was the most frequent manifestation and occurred in 33 patients (43%). The cardiac manifestations were observed in 40 (41%) RA. Pericarditis appeared in 11 patients, valvulopathy in 12 patients and coronaropathy in 11 patients. In 10 of PD diagnosed patients, ECG abnormalities were the only findings. Arrhythmias, conduction disturbances, cardiac failure and coronaropathy were the cardiac manifestations of PSS in 11 patients. Polyarteritis Nodosa patients had myocardial ischemia and another had a malignant hypertension diagnosis. We found pericardial effusion in one patient and angina in another one with MCTD diagnosis. We did'nt find any cardiac manifestation in AS. Cardiac manifestations are frequent in connective tissue diseases. The ECG, ECO and pathology show abnormal findings. Although there is not clinical cardiological expression of the disease we suggest the use of ECG. ECO Holter electrocardiography and isotopic myocardial perfusion scan technics in the clinical evaluation of such patients.