GnRH agonists have been proposed to improve final height in patients with constitutional short stature. We treated 31 girls, aged 11.9 +/- 1 yr (mean +/- SD), with short stature, recent pubertal onset and predicted final height of 155 cm or less with depot triptorelin. During the 23 +/- 4 months of treatment, bone age progression was 0.6 +/- 0.3 bone age yr/yr, and growth velocity declined from 7 +/- 2 to 4 +/- 0.8 cm/yr (P < 0.0001). Height prognosis, calculated by the Bayley-Pinneau method, progressed from 149.6 +/- 3.4 to 151.8 +/- 4 cm at the end of treatment (+2.2 +/- 2.6 cm; P < 0.0001). When treatment was interrupted, growth velocity slightly increased to 4.6 +/- 1.6 cm/yr, and bone age maturation was accelerated: 1.3 +/- 0.4 bone age yr/yr during the first posttreatment year. At the last visit, 26 +/- 9 months after interruption of treatment, bone age was 14.9 +/- 1.3 yr (> or = 13.5 yr in all patients), height was 149.1 +/- 4 cm, and final height prognosis was 150.6 +/- 3.6 cm. Final height prognosis was 1 +/- 2.3 cm greater than pretreatment height prognosis (P < 0.02) and 1.2 +/- 2.2 cm below the height predicted at the end of the treatment (P < 0.01). No major side-effect was observed. Height SD score decreased during treatment with GnRH agonist from -2.3 +/- 0.9 to -2.7 +/- 0.7 SD score (P < 0.0001). We conclude that 2 yr of depot triptorelin-induced pubertal delay has a limited effect on near-final height in girls with constitutional short stature and that the growth benefit observed does not currently justify the use of GnRH agonists, given their cost and potential side-effects.