Several physiological alterations may occur in cardiovascular system during fetal life to the neonatal period. Electrocardiographic studies in neonatal period may assist veterinarians to evaluate cardiovascular system in this period. Five multiparous high producing Holstein dairy cows were monitored at close-up dry period to calving. Electrocardiograms were recorded from their calves immediately and 5, 10, 15, 20, 25, 30 and 35 days after birth and all electrocardiographic parameters were evaluated. Durations of P, R and T waves were increased significantly from birth to the end of neonatal period (P<0.05). R and T amplitudes were significantly elevated but P amplitude declined significantly. There were significant increasing patterns in PR, RR, QT and ST intervals during neonatal period (P<0.05). Based on these findings, it may be suggested that physiological alterations of the electrocardiographic parameters occur during the neonatal period of the Holstein dairy calves at neonatal period. These data could provide a better understanding of interpretation of the electrocardiographic alterations among neonatal calves.