Insulin release and growth are intimately connected. The aim of the present study was to investigate height and weight in diabetic children from birth to onset of Type 1 (insulin-dependent) diabetes mellitus compared to that in referent children. Data on height and weight were collected from mailed questionnaires and from growth records obtained from the child health clinics and schools in 337 recent-onset diabetic children, 0-14 years old, and from 517 age-, sex-, and geographically matched referent children. A total of 9002 paired height and weight observations were collected. The anthropometric development of the children was expressed as standard deviation scores using the National Center for Health Statistics/Centers for Disease Control (NCHS/CDC) growth reference material. On the average, the diabetic children were consistently taller than the referent children, a finding more pronounced among the boys. The diabetic boys were significantly taller from 7 to 1 years before the clinical onset of the disease, regardless of age at onset. A similar tendency was found for the girls. When mean height from 5 to 1 years before onset was used as a possible risk factor for diabetes, a linearly increasing trend in the odds ratio was found for diabetes in boys (odds ratio = 1.0; 1.57; 2.46 for height standard deviation score values less than 0; 0-1 and greater than 1, respectively; p = 0.002 for trend). A similar, but statistically not significant, tendency was found for girls (odds ratio = 1.0; 1.44; 1.43). As regards height increment from birth similar trends in odds ratios were found.(ABSTRACT TRUNCATED AT 250 WORDS)