Diabetic muscle infarction (DMI) is a painful and potentially serious complication in patients with poorly controlled diabetes mellitus. The incidence of DMI is likely much greater than reports in the literature suggest, perhaps secondary to the difficulty in making the diagnosis and excluding other more serious etiologies. This paper describes the role of MRI in the evaluation of a diabetic patient with a painful, swollen limb. Early application of MRI can more accurately classify the disease process and focus the differential diagnosis, thus avoiding the hazards of medical therapy associated with other etiologies such as deep venous thrombosis, cellulitis, or osteomyelitis. This paper describes the evaluation and diagnostic pitfalls encountered in two patients. MRI techniques and applications are presented with a discussion of clinical and radiological differential diagnoses.