Satoyoshi syndrome consists of painful intermittent muscle spasms, alopecia and diarrhea. The age of onset is commonly less than 20 years of age. Adult onset of this syndrome is rare. We report a 65-year-old Japanese woman with Satoyoshi's syndrome of adult onset. Satoyoshi's syndrome of adult onset shows no skeletal abnormalities, in comparison with the classical pediatric cases. The clinical features in our patient revealed the benign and long-term course of muscle spasm and alopecia. This progression differed markedly from the other patients of adult onset. Thus, the severity of Satoyoshi's syndrome is variable in adult onset cases, and this diagnosis should be considered in adults with various and unexplained muscle spasms.