We studied the prevalence of limited joint mobility (LJM) in 100 diabetic children and 100 non-diabetic controls. Our objective was to find possible predictors for the expression and progression of LJM and to evaluate the relationship between LJM and other long-term complications of insulin-dependent diabetes mellitus. LJM was present in 36% of diabetic patients aged 2-20 years. It was significantly related to duration of disease and longitudinal glycated haemoglobin (HbA1c) concentrations, pubertal stage, number of ketoacidosis and skin changes. Fourteen patients had peripheral neuropathy, 16 had microalbuminuria, 8 had nephropathy, and 7 had retinopathy. After matching for duration of disease, HbA1c concentrations and pubertal stage, a comparison of the complication rates was made. All long-term complications were significantly associated with LJM. Longer duration of disease and higher mean longitudinal glycated haemoglobin level are independent predictors for expression of LJM. Thus, improvement of metabolic control in diabetic patients before puberty may diminish the expression and progression of LJM.