Out of a total of 8136 children registered in the Kabi Pharmacia International Growth Study, 12 have been reported to have diabetes either before or during treatment with growth hormone (GH). Two of these have non-insulin-dependent diabetes mellitus (NIDDM), of whom one had risk factors for the development of his condition, namely gross obesity and familial occurrence of NIDDM. One is a rare case of McCune-Albright's syndrome with insulin-dependent diabetes mellitus (IDDM), and 9 other patients have IDDM. Of these 9, 6 have idiopathic GH deficiency. In 8 of the 9 patients with IDDM, the condition was diagnosed before GH therapy was commenced, at ages ranging from less than 2 years to 16 years. The association is probably fortuitous, however, as the onset of IDDM in 7 patients was immediately before or during puberty, as often occurs in IDDM in general.