The aim of this study was to compare the growth response of 22 short pre-pubertal children without growth hormone deficiency, treated with a single daily growth hormone injection (group A), to the growth response of 27 similar children, treated with the same daily dose divided into 2 subcutaneous injections per day (group B), for 1 y, in a randomized study. GH treatment significantly promoted growth parameters, height standard deviation score and height velocity standard deviation score in both groups. Serum insulin-like growth factor I was also increased. There were no significant differences in growth response, serum IGF-I levels, or the advance in bone age between the two study groups after 1 y of GH therapy. We conclude that twice daily s.c. growth hormone injections provide no advantages over once daily injection of the same dose in promoting the linear growth of short children without growth hormone deficiency.