Skeletal growth and development was evaluated in 322 white children (age 6 to 14) using three different methods: (1) 1251 photon absorp tiometry, (2) compact bone measures on radiographs, and ( 3 ) Greulich-Pyle skeletal age from hand-wrist radiographs. Bone mineral content, measured by photon absorptiometry, increased at a n incremental rate of about 8.5% each year. Skeletal age was a poor predictor of skeletal status, i.e., bone mineral content (14% error), and did not decrease the predictive error substantially more than did chronological age. Gross morphology (height and weight) was in fact a better predictor of bone mineral content than were skeletal age, chronological age, and radiographic morphometry. Skeletal age deviations were correlated with deviations in body size. A bone mineral index was devised which was independent of body size and this index was also independent of skeletal age. Skeletal age is imprecise ( 3 to 6 months error) and the range of variation in normal children (13 months) overlaps the maturational delay of the malnourished and diseased. The difficulties in using skeletal maturation are discussed and i t is suggested that particular maturational indices be used which better indicate skeletal growth than does a composite skeletal age.