The T(2)-weighted contrast of peripheral nerve lesions and denervated muscles is the most important diagnostic criterion in neuromuscular MRI. By exactly determining the anatomic denervation pattern of muscles and with a particularly high spatial resolution for peripheral nerves by visualising single fascicles, MRI enables the exact localisation of ulnar nerve lesions in the cubital tunnel or at other sites. Furthermore, the extent of the lesion and the degree of its severity can be evaluated already during the early course of disease. Obviously, MRI is the method of choice for the direct visualisation of causative mass lesions such as ganglion cysts or lipoma, for example, before surgical exploration. Thus, it is a valuable diagnostic tool and supplement to conventional clinical and electrodiagnostic studies of the cubital tunnel syndrome (CuTS). The contribution of MRI to the preoperative selection of patients for either short- or long-segment decompression has to be clarified by further studies.