Although it is a rare occurrence, children can develop both benign and malignant tumors. The most common malignant tumors requiring surgery in childhood are Wilms tumor of the kidneys and neuroblastoma of the adrenal glands. Recognized at an early stage, both are completely curable. Girls may develop benign and malignant tumors of the ovary. Muscle tumors may arise from many different locations. The successful treatment of all of these tumors depends on early diagnosis and a coordinated effort of the pediatric surgeon, the tumor specialist (oncologist), the radiation therapist, and the pediatrician.