This study evaluated the influence of height growth and nutritional status on skeletal maturation of the knee and hand-wrist. Radiographs of 589 subjects (250 girls and 339 boys) from 2 to 15 years were rated according to Greulich-Pyle, TW-20 bone and TW-RUS, RWT knee, and FELS hand-wrist methods and a method combining FELS and RWT indicators. The subjects were referred to the Genoa University Paediatric Department from 1980 to 1987 for short stature, simple obesity, or acute diseases. Bone age was closer to chronological age using the RWT knee method rather than the hand-wrist methods, while bone age assessed at the hand-wrist was closely related to height and BMI. When skeletal maturation was delayed, Greulich-Pyle, TW-20-bone, TW-RUS, and FELS bone ages tended to be lower than RWT knee estimates. Conversely, if maturation was advanced the hand-wrist estimates tended to be higher than RWT knee bone ages. The combined estimates are close to FELS bone age values. These findings show true intraindividual variability of skeletal maturity at the hand-wrist and knee. A certain "laziness" in knee maturation seems to be confirmed. Am. J. Hum. Biol. 12:610-615, 2000. Copyright 2000 Wiley-Liss, Inc.