The aim of this study was to compare vertebral bone mass values of patients with central precocious puberty (CPP) with healthy age and puberty matched controls and to determine the effect of gonadotropin releasing hormone (GnRH) analogs on bone mass in patients who had been treated at least for 1 year. Girls with idiopathic CPP, 11 pretreatment, 14 post-treatment, and 19 pubertal girls as controls were enrolled in the study. The mean ages of the controls and the patients with CPP pre- and post-treatment were 10.25 +/- 1.06, 8.23 +/- 1.11, and 10.36 +/- 1.82 years, respectively. Leuprolide acetate (Lucrin) 3.75 mg was administered s.c. monthly. Bone measurements were performed by dual energy X-ray absorptiometry (DEXA) (Norland) at the anterior-posterior vertebrae (L2-L4). The post-treatment group's mean BMD value was 0.66 +/- 0.12; Z scores according to CA and BA were 0.32 +/- 10 and 0.30 +/- 1.1, respectively. In the study group, BMD values compared to the control group were normal. No significant change in BMD values was observed after treatment. Neither osteopenia nor osteoporosis was observed in patients taking GnRH analog.