Reduced height as a consequence of type-I-diabetes mellitus in childhood has been reported in many studies. However, it is still debated whether good metabolic control can normalize the growth rate. A total of 436 children (204 boys, 232 girls, mean age at diagnosis of diabetes 8.2±0.2 years) were followed at our outpatient diabetes centre. Z-scores for height were evaluated in relation to duration of diabetes, age at onset and long-term metabolic control. At diagnosis, height in children with diabetes was significantly above the reference population (+0.43± 0.09). Standardized height decreased during the subsequent course of diabetes. This likely represents a delay of growth, as the final height (chronological age >18 years, n = 144) was +0.27 ± 0.09. Growth reduction was more pronounced in patients diagnosed before the onset of puberty and final height in patients with a prepubertal onset of diabetes was significantly lower (+0.10 ± 0.13) compared to patients with a pubertal/postpubertal onset (+0.52 ± 0.14). Among patients with a prepubertal onset, the subgroup with “poor” metabolic control (long-term median HbA_1c >7%) lost significantly more height compared to patients with “good” metabolic control.