Idiopathic cardiomegaly is probably the commonest single diagnosis other than hypertension made in tropical and subtropical African cardiovascular practice. Understanding of the nature of this disease has been hampered by failure to recognize the possibility that the term “idiopathic cardiomegaly” may embrace several disease entities. Evidence suggests that many factors, sometimes acting singly, but often acting in combination, may be responsible for the genesis of so-called idiopathic myocardial failure. The future attitude to research should not be one of excluding well-defined forms from the concept of idiopathic cardiomegaly, but one of clinicopathological classification, which should be a prelude to the search, within each moiety of this group of disorders, for a specific or dominant etiological factor.