We have experienced 3 cases of retroperitoneal ganglioneuroma. One case was in a 5-year-old boy with the chief complaint of abdominal mass. The preoperative diagnosis was neuroblastoma due to excessive urinary excretion of vanillylmandelic acid. The other two cases were in adults, 40 and 28 years old, and were found incidentally. All three cases were doing well without any clinical signs of recurrence almost 10 years, 5 years, and 6 months, postoperatively. The literature is reviewed briefly concerning some cases in children under 5 years of age whose ganglioneuromas were sometimes confused with neuroblastoma because of excessive catecholamines.