A retrospective study allowed us to examine 23 cases with aneurysm of the left ventricle. The aneurysm was discovered incidentally in 6 patients, and as a result of cardiac symptoms in an other 14. The diagnosis made following a cerebrovascular accident and an episode of ventricular tachycardia respectively in two cases. Radiological and electrocardiographical investigation revealed the classical findings in 21 cases, while inflammatory changes were also present in 19. Tuberculosis was found to coexist in 4 patients, and was suspected in a further 4. The aetiology of these aneurysms has remained obscure until now. We feel that a debilitating conditions such as tuberculosis or late pregnancy, or perhaps a change in cardiac function, might lead to the development or enlargement of a sub-annular aneurysm in a predisposed subject. One of our patients presented with an apical aneurysm of the left ventricle in association with a complete situs inversus. A further patient had sustained a severe precordial ingiury 10 years previously, and 2 others had a past history of rheumatic joint disease many years previously. It appears to us that cases with calcification have a better prognosis.