A comparative histological and histochemical study on undecalcified frozen sections of the tibial growth plate was performed on fetuses, newborn infants and children. Three types of growth cartilage were described: early fetal, late fetal to newborn, and cartilage of 5- to 10-year-old children. A decrease of cellularity and in increase of matrix, a thickening of the intercolumnar septa, change in metachromasia of the septa and of the basal zone appear with age. A decrease in size of the hypertrophic cells from the early fetal to the newborn period is observed. A system of canals with vascular anastomoses across the plate is well developed in the late fetal-newborn period. Age-dependent change in permeability and in distribution of the oxygen tensions within the plate were suggested. Signs of growth arrest were found in several newborns with important general pathologic findings.