A 38-year-old man who received bone marrow transplantation four years ago for acute lymphocytic leukemia. He felt muscle cramps and became a bed-bound state because of progressing polyarthralgia in the following year. Marked muscle atrophies, mild weakness, joint contractures, and sclerotic skin changes were noted. Motor conduction studies revealed reduction in the amplitude (2.4mV), in the conduction velocity (41m/s), and in the duration (11ms) of compound muscle action potentials in the right median nerve. In concentric needle electromyography, low amplitude polyphasic motor unit potentials discharged with rapid frequency without spontaneous discharges. Mean muscle fiber CV elicited by monopolar needle electrodes were slow compared with normal control. The electrodiagnosis was myopathic change which consists of cluster of atrophic fibers, discriminated from myositis and motor neuron disease. Muscle specimen from autopsy revealed marked atrophied muscle fibers less than 10μm in diameter. There were no necrotic and inflammatory processes. In the fascia, small numbers of infiltrating CD8 positive T lymphocytes with proliferation of collagen fibers were seen, compatible with fasciitis. There were few reports about electrophysiological and pathological findings of fasciitis in cGVHD, which must be focused on the future as distinct from the myositis.