Non-invasive mean arterial blood pressure determinations in twenty-five normal term unmedicated newborn infants from the moment of birth until the end of the first hour of life were performed by a semi-automated electronic oscillometric method. The infants were divided into two groups: A-19 infants with cord clamped at mean = 80 seconds and B-6 infants with cord damped at a mean = 10.3 seconds. Mean arterial blood pressure curves plotted vs. time demonstrated four phases: (1) Primary rise-first 1-2 minutes, (2) Early fall-second to tenth minutes, (3) Secondary rise-tenth to fifteenth minutes, (4) Stabilization after fifteen minutes. The sequence demonstrated is highly suggestive of a functioning autonomic nervous system with chemoreceptor and baroreceptor input from birth. Early clamped infants consistently demonstrated lower pressures after the third minute of life.