It is well known that painful muscle cramps occur frequently in patients with advanced liver cirrhosis (LC). Although many studies discuss the pathophysiological causes of these muscle cramps in various conditions, the results are not clear as far as the cause associated to LC is concerned. In order to investigate the cause of muscle cramps in LC, we examined the histological findings of skeletal muscle fibers in LC rat model and in a patient with LC. LC (n=9) was induced in rats by chronic carbon tetrachloride administration. The histological findings of skeletal muscle tissues from the lower leg in LC rats and those of the upper arm in a patient with LC were compared. The degenerated muscle fibers and centronucleus in LC rats were similar to the opaque fibers frequently observed in myotonic dystrophy with severe muscle rigidity in patients with LC. In conclusion, results of this study suggest that one of the causes for muscle cramps in patients with LC is due to skeletal muscle fiber degeneration. Therefore, histological observation of skeletal muscle fibers should be considered in the treatment of painful muscle cramps.