Limited joint mobility (LJM) of the hand was present in 32 of 100 subjects, aged 3–22 yr, with type I diabetes mellitus. Prevalence of LJM was independent of age and sex, but increased with duration of diabetes, with peak occurrence in individuals who had diabetes for more than 5 yr (P < 0.005). In ageand duration-matched pairs of control and LJM subjects (N = 31), there was no significant correlation of LJM with insulin type, insulin allergy, family history of arthritis, or growth retardation. There was also no correlation with “control parameters” including number of episodes of hypoglycemia and ketoacidosis, degree of ketonuria or mean glucose, hemoglobin A1, fasting triglyceride, or cholesterol value.