Previous cross-sectional studies have shown that limited joint mobility (LJM) is associated with microvascular complications in diabetic patients. This study was performed to see whether LJM predicts the development of other diabetic complications and which factors predispose to the development of LJM. A total of 206 Type 1 diabetic patients (mean age 30.0 +/- 9.5 (SD) years) was studied at baseline. The follow-up study was performed 5 years later in 167 of 206 (81.1%) patients. At the baseline the presence of LJM was assessed by asking patients to approximate the palmar surfaces of fingers in a praying position with fingers fanned and the wrists maximally flexed. LJM was confirmed by passive extension. At the follow-up LJM was first reassessed by the same method and then further studied by goniometer and classified by the method of Rosenbloom. The diabetic patients were assessed in terms of the following complications: background and proliferative retinopathy, peripheral symmetrical polyneuropathy, and clinical nephropathy. The prevalence of LJM was 52.9% at baseline. The odds ratio for proliferative retinopathy was 3.3 (95% confidence interval 1.2-9.5) and for neuropathy 2.5 (95% confidence interval 1.2-5.3) in diabetic patients with LJM compared to patients without LJM, when the confounding effect of the duration of diabetes, age and the body mass index was excluded. LJM developed in 30 patients during the 5-year follow-up (7% per year) and its development was not predicted by any of the microvascular complications at baseline. Proliferative retinopathy developed in 4 of 51 (7.8%) patients with and 3 of 63 (4.8%) patients without LJM at baseline (p = 0.3). Nephropathy developed in 11 of 56 (19.6%) patients with and 11 of 66 (16.7%) patients without LJM at baseline (p = 0.7) and peripheral symmetrical neuropathy in 14 of 45 (31.1%) and 20 of 64 (31.3%) patients respectively (p = 1.0). LJM did not predict diabetic microvascular complications or vice versa. Since LJM is associated with microvascular complications in cross-sectional studies, the clinical value of the assessment of LJM is limited to an orienteering examination in the clinical evaluation of a diabetic patient.