Cardiovascular changes has been reported eating and digestion. Experimental studies showed an early rise in cardiac output during eating which was attributable to an increased heart rate. This changes reverted to baseline valuse at the end of eating. To investigate postprandial cardiac functional change, we studied 20 healthy young men(average age 27 years) nonivasively with BP measurement, electrocardiography and M-mode echocardiohrapy before, 30 minutes and 3 hours after a lunch(600 Kcal). There was no significant changes in mean blood pressure after eating. On echocardiography, diastolic and systolic left ventricular internal dimensions were 4.9±0.4 and 3.1±0.4cm before meal and 4.9±0.4 and 2.9±0.3cm 30 minutes after eating. There was an average increase of 9% in cardiac output 30 minutes after meal. Fractional shortening was 36.4±6.4% before meal and 40.4±6.1(p<0.05) 30 minutes after eating. Ejection fraction changed from 73.5±7.9% to 78.2±6.3%(p<0.05) at postprandial 30 minutes. Myocardial contractility index assessed by the ratio of systolic BP to end-systolic volume was 4.3±1.6mgHg/ml before and 5.3±2.2mmHg/ml 30 minutes after eating. Peripheral resistance index as the ratio of mean blood pressure divided by cardiac index changed from 2,536±1,120dynes·S·cm^-5/m² to 2,048±472dynes·S·cm^-5/m² at postprandial 30 minutes. Electorcardiographic study revealed no changes in ST SE segment, T wave and heart rate after a meal. In conclusion, the increase of cardiac output after a moderate meal in healthy young men was associated with an increase in myocardial contractility and a decrease in peripheral vascular resistance.