Patients with Turner syndrome were treated with recombinant human growth hormone (GH) for 3 years. Sixty-eight patients received GH, 0.5 IU/kg/week, while 93 received GH, 1.0 IU/kg/week, by daily subcutaneous injection. Both treatment groups showed a statistically significant increase in growth during treatment. However, the higher dose increased height velocity to a significantly greater extent during the first and second year of treatment. The projected adult height was exceeded by 52 of 71 patients over the age of 14 years. Plasma insulin-like growth factor 1 levels were elevated and no remarkable advances in bone age were observed. There were no other significant changes in physical or laboratory parameters. No glucose intolerance was observed. These results indicate that GH treatment is useful for accelerating growth velocity in patients with Turner syndrome. However, further study will be required to find the most appropriate dose.