Compressive neuropathy in the upper extremity can be clinically diagnosed by careful history taking, physical examination of the involved nerve. Electrodiagnosis for the suspected nerve informs severity of compression of the involved nerve and indicates specific site of the lesion. In the early stage of the disease, non-operative treatment generally cures the symptom, however, if the conservative treatment fails, confirmation of the exact site of the lesion should be preceded before the operation. Recently, ultrasonography, as a supportive tool for the diagnosis of compressive neuropathy has increasing popularity for its ability to find space occupying lesion, anatomical change of the nerve, and the pathologic change in the nerve itself. For the successful treatment of the compressive neuropathy, these various diagnostic tools have to be introduced in the orthopaedic clinic.