<p>Collagen diseases are chronic inflammatory disorders that systematically affect connective tissues of the entire body, including the skin, joints, and kidneys. Cardiac involvement is not uncommon in collagen diseases. Pulmonary hypertension is the most prevalent complication, followed by systolic and diastolic dysfunction, conduction abnormalities, perimyocarditis, and valvular disease. The recent advent of echocardiographic techniques has enabled the detection of subclinical cardiac changes in collagen diseases. In systemic sclerosis, exercise echocardiography can unmask pulmonary artery hypertension. Speckle tracking echocardiography applied to the right ventricle in systemic sclerosis is useful for assessing the degree of chronic right ventricular pressure overload in addition to the irreversible pathological processes affecting the pulmonary vasculature. In systemic lupus erythematosus, three-dimensional echocardiography provides a clearer visualization of Libman-Sacks endocarditis lesions compared to two-dimensional echocardiography. Dermatomyositis, as well as rheumatoid arthritis, has traditionally been associated with pericardial effusion due to perimyocarditis and, more recently, with diastolic dysfunction and myocardial hypertrophy.　Here, we present echocardiographic findings for representative types of collagen diseases, highlighting their characteristic features and providing accompanying images for each.</p>