Gonadotropin-releasing hormone agonists (GnRHa) are the treatment of choice for central precocious puberty (CPP) and have been widely used for several decades. We determined the effect of GnRHa treatment on the auxological outcomes of girls with idiopathic CPP. This study included 84 girls treated monthly with depot leuprolide acetate who had reached adult height. We compared their final adult height (FAH) with their initial predicted adult height (PAH). We performed a multivariate analysis of the factors associated with FAH on all girls diagnosed with CPP. We performed the final evaluations at a mean age of 14.1 ± 0.8 years after a mean treatment duration of 2.98 ± 0.73 years (ranging from 1.5-4.8 years). Menarche had occurred at 12.6 ± 0.6 years of age, which was 16.5 ± 6.1 months after discontinuation of GnRHa therapy. Mean FAH was 160.1 ± 5.0 cm, which was significantly higher than the initial PAH (156.1 ± 5.7 cm; P < 0.001). To investigate whether growth outcomes were influenced by the age at initial treatment, we divided all patients into two groups, those treated between 6 and 8 years (n = 23) and those treated after 8 years (n = 61); no significant differences were observed in FAH between the two groups. FAH was significantly and positively correlated with the height standard deviation score (SDS) at the end of treatment and with the target height, whereas the difference between bone age and chronological age at the start and end of treatment was negatively correlated with FAH. FAH was significantly higher than the initial PAH in girls with CPP who were treated with GnRHa. Also, GnRHa treatment was still effective even after 8 years of age in girls with CPP.