A 52-year-old unmarried bag craftsman was admitted to East Tokyo Metropolitan Hospital because of a large scrotal hematoma. He had accidentally hit his right testis against the edge of a desk early the previous morning. He had resected his right testis with scissors to release from severe pain 30 min after the accident. He had sutured the scrotal incision with two stitches of string by himself. At the emergency operation 36 h after the self-mutilation, we removed a hematoma weighing 283 g and ligated the cut end of the right spermatic cord after adequate debridement. He was diagnosed by a psychiatrist as having slightly low intelligence without psychotic disorder or drug abuse.