Restrictive cardiomyopathies constitute a heterogenous group of heart muscle conditions that all have, in common, the symptoms of heart failure. Diastolic dysfunction with preserved systolic function is often the only echocardiographic abnormality that may be noted, although systolic dysfunction may also be an integral part of some specific pathologies, particularly in the most advanced cases such as amyloid infiltration of the heart. By far, the majority of restrictive cardiomyopathies are secondary to a systemic disorder such as amyloidosis, sarcoidosis, scleroderma, haemochromatosis, eosinophilic heart disease, or as a result of radiation treatment. The much more rare diagnosis of idiopathic restrictive cardiomyopathy is supported only by the absence of specific pathology on either endomyocardial biopsies or at post-mortem. Restrictive cardiomyopathy is diagnosed based on medical history, physical examination, and tests: such as blood tests, electrocardiogram, chest X-ray, echocardiography, and magnetic resonance imaging. With its wide availability, echocardiography is probably the most important investigation to identify the left ventricular dysfunction and should be performed early and by groups that are familiar with the wide variety of aetiologies. Finally, on rare occasions, the differential diagnosis from constrictive pericarditis may be necessary.