The true myxoma of the retroperitoneal region is a relatively rare neoplasm of primitive mesenchyme, which is generally being, however, recurrences frequently develop after incomplete surgery. A pelvic retroperitoneal myxoma was operated at the Department od Obstetrics and Gynecology, Medical College Hospital, Pusan National University and a follow-up period of 2year and 2 month has been obtained with no recurrence. The patient was a 32-year-old Korean female in 1967. In 1961, the patient underwent abdominal total hysterectomy and left salpingo-oophorectomy for destructive mole. In October, 1967, a right lower abdominal mass was palpated and on November 27, 1967, the pelvic retroperitoneal mass was enucleated and the right tube and ovary were infact. The operative specimen was an ovoid,, white-gray, and soft mass, weighing approximately 410gm, and the microscopic diagnosis was retroperitoneal myxoma.