The relationship between short stature and school performance was examined by comparing an unselected cohort of 140 'normal' short children (below 3rd centile) aged between 7 and 9 years with 140 control children of normal height (10th-90th centiles). The short children had unimpaired self-esteem and normal patterns of behaviour, but a tendency towards hyperactivity and poor concentration. Their IQ scores were normal, but attainment, especially in reading, was low. The underachievement observed in the short children is largely due to the low socio-economic status of this group. All the children in the study were prepubertal and these data will serve as a baseline for further follow-up during and after puberty.