Although it has been well established that GH treatment increases final height (FH) in girls with Turner syndrome (TS), the optimal ages to start GH therapy and introduce estrogens for pubertal induction have not been defined. We evaluated retrospectively the influence of the age at onset of GH treatment and age at onset of puberty on FH of 186 adult TS women treated during childhood with GH. Puberty started spontaneously in 38 patients, and it was induced in 148 girls with ethinyl estradiol (mean +/- SD starting dose, 66 +/- 32 ng/kg.d). Patients with spontaneous or induced puberty were divided into quartiles on the basis of age at initiation of GH treatment (3-10, 10-12, 12-14, and 14-19 yr). FH was 151.7 +/- 6.0 cm; there were no FH differences between patients with induced or spontaneous puberty, nor were there differences between the age quartiles. Puberty started earlier in the girls with spontaneous puberty than in those with induced puberty (12.4 +/- 1.3 yr vs. 14.5 +/- 1.9 yr; P < 0.0001). The age at onset of puberty was not related to FH. Pubertal growth was 15.4 +/- 4.6 cm in the girls with spontaneous puberty and 8.6 +/- 4.3 cm in the girls with induced puberty (P < 0.0001). We conclude that GH treatment results in a significant increase in FH in most TS girls. Under the conditions of GH treatment and induction of puberty that we have used, the age at start of GH treatment was not related to FH; in addition, late or delayed induced or spontaneous puberty did not affect FH.