A community based epidemiological study of coronary heart disease (CHD) was carried out in a random sample of 13723 adults in the age group of 25-64 years in the urban population of Delhi. The electrocardiogram (ECG) of all clinically detected CHD cases and of a sample of 5621 persons (selected on the basis of alternate household screened) without clinical manifestations of CHD, was obtained. Out of 5621 persons labelled as asymptomatic, CHD evidence of Q wave myocardial infarction (MI) was present in 80 ECGs (1.4%). Another 296 ECGs had ST & T changes vide Minnesota Code 4-1-1, 4-1-2, 5-1 and 5-2 acceptable as evidence of probable CHD. The overall prevalence rate of asymptomatic CHD was 6.7% (male 5.6%, female 7.6%). Silent MI was more common in the male patients (1.7% vs 1.1%, p < 0.001). However, ST-T changes were more common in female patients (6.5% vs 3.9%, p < 0.001). The ST-T changes showed a steady factor in asymptomatic CHD cases was hypertension in both sexes (male-45.2%, female-43.5%) p = NS. Obesity was present in 24% of male & 46.1% of female patients (p < 0.001). Family history was found in 20% cases of both sexes. Smoking was recorded in 34.9% male and 10.9% female patients with asymptomatic CHD (p < 0.001).