The objective was to evaluate the prevalence of right ventricular myocardial infarction (RVMI) in patients with acute inferior wall myocardial infarction (IWMI) admitted to the National Institute of Cardiovascular Diseases, Karachi, Pakistan. Between August 2000 and May 2001, a total of 100 patients with acute IWMI were enrolled. History of all patients was taken, and thorough clinical examination was performed to asses the presence of signs of right ventricular infarction. Standard 12-lead electrocardiogram was recorded immediately on arrival of patients along with right precordial leads. All patients were considered for thrombolytic therapy in the absence of any contraindication and were managed with standard treatment strategies. Complications arising during the course of admission were recorded and compared between the two groups. There were 86 (86%) males and 14 (14%) females. Mean age was 56.3 +/- 13.13 years (range 33-83 years). The prevalence of RVMI in IWMI was 34%. Smoking and diabetes were more prevalent in RVMI group, while hypertension and family history of ischemic heart disease were more common in isolated IWMI. Ninety per cent of patients received thrombolytic therapy. In-hospital mortality (23.5%) was higher in RVMI group than isolated IWMI (18.1%). Other major complications were also higher in RVMI group than isolated IWMI. Right ventricular infarction was found in approximately one-third of IWMI. Right ventricular infarction was associated with considerable morbidity and mortality, and its presence defines a higher risk subgroup of patients with inferior wall left ventricular infarction.