Twenty patients with growth hormone deficiency ranging in age from 5 5/12 to 15 8/12 years were treated for 12 months with a combination of human growth hormone and oxandrolone, followed by a period of six months off both medications. Eight of the patients received the combined therapy during the first year of hGH treatment, and 12 during either the second or fourth years of hGH administration. In considering growth velocity alone, the addition of anabolic steroid was beneficial. The bone age advanced rapidly when oxandrolone was added during the first year of hGH treatment, and less rapidly in subsequent years. The increased growth velocity, however, compensated for the acceleration of bone maturation and the overall effect of the combined treatment was beneficial, particularly when used after the first year of hGH treatment. We conclude that there is no advantage to using oxandrolone during the first year of hGH therapy, that oxandrolone in the appropriate dose is of benefit in subsequent years of hGH treatment, and that because of the individual variation in bone maturation, bone age should be frequently assessed.