Background. Limited joint mobility (LJM) is a common but seldom diagnosed musculoskeletal complication of diabetes. The purpose of this study was to estimate the prevalence of LJM among Type 1 and Type 2 diabetics and the relationship of LJM to age, duration of the disease, control of diabetes, and mobility of the wrist. Material and methods. Joint mobility was assessed in 77 type 1 diabetics and 111 type 2 using the "prayer sign" and "table sign." The subjects were also examined for active flexion of the wrist. The relationship between LJM and these parameters was analyzed, using the G test, the Lilliefor test, t-Student, t-Welch, and U-Mann-Whitney. Results. LJM is a common symptom (40.26% in Type 1, 67.67% in Type 2) and sometimes the first clinically apparent complication of diabetes in youth and adults. In Type 2 patients LJM was significantly more often diagnosed (p<0.001). In both types of diabetes the mobility of the wrist was significantly reduced (p<0.001) and there was significant correlation between LJM, duration of diabetes (p = 0.039 for Type 1, p = 0.026 for type 2) and the metabolic control of diabetes (evaluated by the average glycosylated hemoglobin A (p = 0.021 for type 1, p < 0.001 for type 2). Conclusion. The easy to perform "prayer sign" and "table sign" are useful in assessing joint mobility, and should be used for screening in the initial diagnosis of diabetic complications. Early prophylaxis and treatment (rigorous metabolic control and rehabilitation) may reduce the risk of handicap.