BACKGROUND Modern treatment of central precocious puberty (CPP) by agonist analogues of gonadoliberin (aGnRH) block the development of secondary sex characteristics, it delays bone maturation and improves the prospects of reaching optimal height. The objective of the present study was to compare the effect of formerly used treatment with synthetic progestin, Cyproterone acetate (Androcur, Schering), with contemporary treatment using aGnRH Triptoreline (D-Trp-6-LHRH, Decapeptyl depot, Ferring) on growth parameters of female patients. RESULTS The authors treated 12 girls with CPP. The first group comprised 7 girls treated solely with Cyproterone acetate (first signs of CPP at the age of 4.9 +/- 1.8 years, onset of study at calendar age (CA) 7.1 +/- 1.3 years, bone age (BA) 10.2 +/- 1.3 years, follow-up period 1.8 +/- 0.8 years). The second group was formed by five girls originally treated for a period of 1.8 +/- 1.7 years (4-56 months) with Cyproterone acetate and subsequently with Triptoreline for a period of 1.5 +/- 0.3 years. The latter group developed signs of CPP at the age of 4.9 +/- 2.6 years. At the onset of Triptoreline treatment and thus at the onset of the study the girls' age was 7.4 +/- 0.7 years and BA 9.6 +/- 1.9 years. Secondary sex characteristics did not progress in either of the investigated groups during the study period. The authors observed in both groups before the investigation an acceleration of BA per calendar year (dBA/CA) of 1.5 +/- 0.6 SD (p < 0.01), as compared with standards of the healthy population. In the course of the investigation in the first group dBA/CA of 1.4 +/- 0.6 years (p < 0.01) persisted, in the second group a decline of dBA/CA to a normal level occurred (0.9 +/- 0.4 years). The growth rate in the two groups did not differ during the investigation from standards for the healthy population. Height in relation to bone age (BH/BA SDS) declined in the first group during the investigation from -1.8 +/- 0.9 SDS to -2.2 +/- 1.0 SDS (p = 0.06). In the second group this indicator did not change. CONCLUSIONS During Triptoreline treatment, as compared with Cyproterone acetate treatment, in patients with CPP the rate of bone maturation declined to normal and their height in relation to bone age did not decline. This led to the assumption of a smaller future adult height loss in patients treated with aGnRH Triptoreline.