The primary objective of this study was to assess how HIV has influenced the spectrum of heart diseases in Botswana and to examine the HIV prevalence among patients with cardiomegaly. The secondary objective was to evaluate the value of the cardiothoracic (CT) ratio on chest radiography (CXR) as a screening tool for cardiac disease. In total, 179 patients (age 14-97 years) with cardiomegaly (all CT ratios >0.53 on CXR) and known HIV status were referred to Botswana's sole hospital-based echocardiographic centre. Clinical examination and echocardiography were performed. Cardiomyopathy (36.9%), pericarditis (21.2%), hypertensive heart disease (14.0%), rheumatic heart disease (8.4%) and right-sided heart failure (6.7%) were the main causes of cardiomegaly; only two patients had a normal echocardiogram. The HIV prevalence was higher than in the general population [59% vs 25%; relative risk (RR) of HIV infection compared with the general population 2.4, 95% CI 2.1-2.7]. HIV infection was strongly associated with pericarditis (RR 3.3, 95% CI 2.8-3.8) and cardiomyopathy (RR 2.9, 95% CI 2.4-3.5). These data suggest an increased risk of non-ischaemic heart disease, in particular pericarditis and cardiomyopathy, among HIV-infected patients. The CT ratio on CXR had high specificity in detecting severe heart disease and can be a useful screening tool in areas with limited resources.