Migration of a peritoneal catheter of a ventriculoperitoneal shunt into the scrotum is a rare complication. We treated a case of catheter migration in the scrotum. A 12-year old boy, who had had a ventriculoperitoneal shunt at the age of 4 months due to neonatal hydrocephalus, visited the outpatient clinic because of a right inguinal hernia. On physical examination, a firm mass was found in the left scrotum. Pelvic X-ray demonstrated a coiled catheter in the left scrotum. The catheter was successfully removed by exploring the left patent processus vaginalis after high ligation of the hernia sac. This case suggests a suction action of the patent processus vaginalis and the possibility of catheter migration long after shunt catheter insertion.