Diabetes mellitus is a known risk factor for frozen shoulder. This study was performed to quantify this association and test any relationship with other risk factors for diabetic complications. Patients attending diabetic (n = 865) and general medical (n = 202) clinics were interviewed and examined. External rotation was measured in both shoulders. Glycated hemoglobin A(1c) was measured in all diabetic patients. Frozen shoulder was defined as pain for more than 3 months and external rotation of less than 50% of the unaffected shoulder. Bilateral frozen shoulder was defined as external rotation of less than 30 degrees in both shoulders. Shoulder pain was present in 25.7% of diabetic patients compared with 5.0% of general medical patients. The criteria for frozen shoulder were fulfilled in 4.3% of diabetic patients and in 0.5% of the general medical patients. Only duration of diabetes had a positive association. The prevalence of painful or stiff shoulder was greater in diabetic patients than general medical patients. The prevalence of frozen shoulder is less than previously reported but still greater in diabetic patients.