Thirty-four girls with precocious puberty (27 idiopathic, 6 cerebral, 1 McCune-Albright syndrome) were treated with cyproterone acetate (CPA) for 1.2-8.4 years (3.71 +/- 0.31; mean +/- SEM) at a daily dosage of 66-150 mg/m2 (103.7 +/- 6.2). The mean chronological age (CA) and bone age at the beginning of treatment were 5.99 +/- 0.31 and 8.6 +/- 0.39 years, respectively, and 9.78 +/- 0.19 and 12.44 +/- 0.22 years, respectively, at the end of therapy. At the last evaluation, mean CA was 14.23 +/- 0.4 years, and 32 girls had reached final height. The control group consisted of 10 girls with idiopathic precocious puberty who, at their parents' request, were not treated. Mean CA at the onset of pubertal signs was 6.05 +/- 0.25 years. All patients had reached final height at the time of the last observation. There was no significant difference between final height of treated (152.43 +/- 1.36 cm) and untreated (149.55 +/- 1.99 cm) girls. Final height was significantly lower than target height in both treated (155.08 +/- 0.92 cm; p < 0.025) and untreated (156.45 +/- 1.29 cm; p < 0.0005) patients, but the mean height of treated patients is nearer to target height than that of untreated ones. A positive correlation was found between final height and target height both in treated (p < 0.005) and untreated (p < 0.05) patients. After the discontinuation of CPA treatment all girls resumed the progressive course of puberty.(ABSTRACT TRUNCATED AT 250 WORDS)