It is obvious that cardiac functions are as important as the respiratory system in adaptation to postnatal life. However, type of delivery is supposed to affect cardiac function. For this reason, cardiac output, ejection fraction, fractional shortening, left ventricular end diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD), right ventricular end diastolic diameter (RVEDD), right ventricular end systolic diameter (RVESD) and left atrium/aorta diameter ratio (LA/Aorta) were measured by color Doppler echocardiography at the in 15 neonates delivered vaginally (Group 1) and in 15 neonates first hour and at the 7th day of delivered with elective cesarean section (Group 2). Additionally, heart rate and mean blood pressures were recorded at the same time periods. At the measurement of the first hour of life, mean blood pressure (52.2±6.87 vs 46.8±4.68 mmHg), heart rate (156.2±9.7 vs 147.5±12.7/min), LVESD (14.0±1.69 vs 12.71±0.38 ml) and LA/Aorta ratio (1.35±0.16 vs 1.21±0.19) measurements of Group 2 were found to be higher than those of Group 1 (p<0.05 for each item). However, no difference was noted at the 7^th days measurements. These results show that type of delivery has significant effect on cardiac functions in early adaptation to postnatal life. Neonates delivered vaginally have hemodynamic advantages over neonates delivered with elective cesarean section in the early hours of life but this difference seems to disappear at the 7^th day. These results may be explained by maternal physiologic oxytocin transferred to the fetus during vaginal delivery. Oxytocin may affect its cardiac receptors and/or may increase atrial natriuretic peptide related natriuresis and diuresis leading to volume load reduction. Anahtar Kelimeler : yenidoğan, ekokardiyografi, doğum şekli, postnatal adaptasyon, newborn, echocardiography, delivery type, postnatal adaptation.