The aim of the work: The 24 hour rhythm study of cord’s electrical activity adaptation in healthy newborns in the first 72 hours after birth and on the 5th day of life. Materials and methods: The studies were performed in 46 healthy new-borns taken from healthy women having a normal physiological pregnancy evolution. The electrocardiogramm in 12 derivations was registered at “Mingograf-34” (Siemens-Elema) in the first 60 minutes of new-borns’ life, then, each 3 hour during 72 hours and on the 5th day after birth. Results: The electrocardiographic investigations in healthy new-borns in the first 60 minutes after birth have pointed to the fact that in comparison with the subsequent period of time, the increased cord’s contractions frequency, the high amplitude of waves P and R in derivations II, III, aVF, V1-2 and a lower length of cord’s conductivity. Conclusions: The adaptation of the cord’s electrical function in healthy new-borns in the first 5 days of life happens according to a chronobiologycal rhythm, which is expressed by means of decline in the cardiac activity periods in the first 12 hours after birth and from 42 hours till 60 hours as well through periods of increase in the cardiac function from 15 hours till 39 hours and from 63 hours till 72 hours. On the 5th day of new-borns’ life is estimated the decrease in the overdemand of the right myocardium and the increase of the cardiac activity, as a result of pulmonary hemodynamics stabilization.