In the present study, data from 230 short children born small for gestational age, who were participating in four clinical trials, were pooled and analysed. At the start of GH treatment, median age and height SDS were 5.3 years and -3.2 SDS, respectively. A dose-dependent increase in height SDS was observed following 2 years of GH treatment: 1.1, 1.7 and 2.5 SDS for the three GH treatment groups (0.1, 0.2 and 0.3 IU/kg/day, respectively), compared with an increase of 0.14 SDS in the control group. In a multiple regression analysis, four variables were found to correlate independently with the gain in height SDS following 2 years of GH treatment. These are given below in order of importance: gain in height SDS = 7.7 x dose of GH (IU/kg/day) -0.11 x age (years) -0.08 x parental-adjusted height SDS + 0.05 x birth length SDS (SD = 0.5; r2 = 0.64). At the end of the 2-year study period, a total of 48%, 66% and 90% of patients in the groups given GH at 0.1, 0.2 and 0.3 IU/kg/day, respectively, had a parental-adjusted height greater than -1.0 SDS.