We report a case of Klinefelter syndrome with the chief complaint of male infertility. Normal pregnancy and delivery resulting from conventional testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI) was possible by a previous doctor when he was 31 years old. He was referred to our hospital for treatment of infertility when he was 41 years old. Abdominal ultrasonography demonstrated a low echoic region with a relatively uniform content in the left testis and a central low echoic small mass surrounded by a high echoic region in the right testis. In excised tissue of the left testis, only a single seminiferous tubule containing spermatozoa was found and sperm was successfully retrieved by microdissection TESE.