A case of 48XXYY Klinefelter's syndrome diagnosed with foot ulcers, in a 43-year-old man, is reported. He presented to the Department of Dermatology in our hospital with the chief complaint of recurrent foot ulcers. He was referred to us because of atrophic external genitalia. The present condition and endocrinological examination suggested Klinefelter's syndrome. Chromosomal analysis revealed that his chromosomal type is 48XXYY. This is the 24th case of Klinefelter's syndrome with 48XXYY chromosome and is the 5th case associated with foot ulcers in Japan. Here we report this case together with a brief review of the previously reported cases.