We examined the association between slipped capital femoral epiphysis (SCFE) and growth hormone (GH) treatment in 16,514 children who had not been treated with GH prior to their enrollment in the National Cooperative Growth Study. Fifteen children had SCFE prior to receiving GH therapy, 26 developed SCFE during GH treatment, and one had SCFE on one side prior to GH treatment and developed it on the contralateral side while receiving GH. Children with GH deficiency were significantly more likely to develop SCFE while on GH treatment than were children with idiopathic short stature (p = 0.006). There was no difference between GH-deficient girls and boys in the risk of developing SCFE during GH treatment. There were 3 cases of SCFE in girls with Turner syndrome before GH treatment and 3 during. Typically, children who developed SCFE while on GH were older, heavier, and grew more slowly during the first year of GH than those who did not. Children with GH deficiency, Turner syndrome, and other known causes of short stature are more likely to develop SCFE before or during GH treatment than children with idiopathic short stature.