Purpose of the present study was to investigate the early cortical somatosensory evoked potentials after median nerve stimulation and to determine normative data as a function of age. Two hundred forty subjects aged 1 day to 18 years were studied to determine standards of normality during maturation to establish the growth curve. The N9, N13, and N20 components were present in all patients. These components decreased in latency until 4 to 5 years of age because of central nervous system maturation after which latencies increased until adulthood, on the basis of brain and body growth.