Values have been presented in tabular and graphic form for the amounts of growth observed in the femur and tibia as related to specific chronological and skeletal ages. These figures were derived from serial orthoroentgenographic measurements of normal lower extremities in fifty girls and fifty boys whose growth had been recorded at annual intervals over the last eight years preceding epiphyseal fusion. Certain reference data were also provided on the stature, the lengths of the femora and tibiae, and the skeletal age assessments of these 100 children at each age. A revised growth chart was described which may be used as a guide in estimating the effects of epiphyseal arrest at the distal end of the femur and proximal end of the tibia. Certain factors which may influence the amount of correction of discrepancy obtained through epiphyseal arrest were discussed in some detail; these included the factors producing the discrepancy and its rate of increase, the child's maturity relative to his age in years, his pattern of growth, and his relative size for age.