Oxandrolone administered in the dose of 0.25 mg/kg/day for two six-month intervals, each followed by a six-month period of observation, was associated with acceleration of skeletal maturation to a greater degree than linear growth in eight of nine children. Five of nine children showed decreases in predicted mature height (mean loss of 3.1 cm), with the greatest reduction occurring in subjects with youngest skeletal ages at the time therapy was begun. Excessive virilization and liver dysfunction were not noted. Oxandrolone therapy in constitutional growth retardation appears to be associated with considerable skeletal maturation and risk to ultimate adult height.