In the past 15 years 450 girls have been seen because of concern about tall stature: 168 of them have been treated with stilbestrol to control the growth rate. Of the latter group 87 have been followed after treatment for a sufficiently long time to be sure growth had ceased and to provide the data for this report. At the onset of treatment the following data (mean values) were recorded: chronologic age, 13.0 years; skeletal age, 13.2 years; height, 172.9 cm; estimated mature height 180.2 cm; and growth potential, 7.3 cm. At the end of treatment data of interest (mean values) were: reduction in final height, 3.5 cm; duration of therapy, 2.1 years; amount of stilbestrol given, 2.3 gm; age of last visit, 17.6 years. Side effects were minimal, though two girls developed parovarian cysts that required surgery during treatment. Not included in the series of 87, one additional girl was seen with a serous cystadenoma of the ovary, and one girl developed superficial venous thrombosis of the calf. Long-term follow-up has revealed no late complications. It is concluded that estrogen can reduce significantly the growth rate of almost all tall girls, but treatment must be carried out under very careful supervision, bearing in mind possible side effects.