20 girls, their age being between 8 to 13 years, with an actual height above the 97th percentile received 10,0 mg conjugated estrogens per day cyclicly or 0,3 mg ethinylestradiol continuously over a period of 0,3 to 3,8 years, in order to inhibit excessive growth. The duration of therapy ranged from 0,6 to 3,8 years regularly. Before and during treatment the patients were examined, and each time the expected final height was calculated based on the actual height and the bone age. The stage of puberty was defined according to Blizzard, and the determination of the bone age was performed as described by Tanner and Whitehouse. The extragenital side effects were also recorded. The effectiveness of the estrogen treatment, i. e. the reduction of the expected final height, depends on the chronological age, the skeletal age and the stage of puberty before therapy. It ranged between 0,5 and 5,1 cm. The earlier treatment was started the better were the results. The effectiveness was more obvious in cases with continuous estrogen treatment. No serious side effects could be observed.