Background/Aims: The effects of biosynthetic human growth hormone (r-hGH) in children with familial short stature (FSS) are varied. We determined whether responsivity to r-hGH in FSS is dose-dependent. Method: Randomised trial of two doses (20 or 40 IU/m<sup>2</sup> body surface area/week by daily subcutaneous injection) of r-hGH in 29 (24 male, 5 female) FSS children with assessment at adult height. Results: Age range at presentation was 5.1–10.5 years, height less than 1.5 standard deviation scores (SDS) below the mean, height velocity SDS greater than –1.5 and peak growth hormone response to provocative testing over 13.5 mU/l. Adult height data (SDS) at 16.5 ± 2.1 years for the low-dose group and 16.1 ± 1.1 years for the high-dose group (p = 0.62) were similar [low dose –1.06 (SD 0.75), high dose –1.02 (SD 0.83); p = 0.88]. The incremental effect of both doses on stature was minimal [low-dose difference in height actual-predicted 0.79 (SD 0.94), high dose 1.27 (SD 0.88); p = 0.12]. Conclusion: Using this r-hGH dosing schedule there were little short- or long-term effects on height in children with FSS.