Final adult height is often compromised in children with congenital adrenal hyperplasia (CAH). This study examines the impact of GH and LHRH analog (LHRHa) on final adult height in patients with CAH due to 21-hydroxylase deficiency. Fourteen patients with CAH (eight males, six females) predicted to be more than 1.0 sd below their midparental target height received GH and LHRHa until final height. Each patient was matched at the start of GH therapy to a CAH patient treated only with glucocorticoids according to type of CAH, sex, and chronological age. Mean age, bone age, height, height prediction, and target height were the same in both groups at the beginning of GH therapy. Mean duration of GH treatment was 4.4 +/- 1.5 yr. Mean duration of LHRHa therapy was 4.2 +/- 2.0 yr. In the treatment group, final height sd score of -0.4 + 0.8 was significantly greater than both the initial prediction of -1.5 +/- 0.9 (P < 0.0001) and the final height sd score of the untreated group of -1.4 +/- 1.1 (P = 0.01). Our results indicate that the combination of GH and LHRHa improves final adult height in patients with CAH.