Occurrence of benign tumors in large pediatric population have never been studied. Basing on the data on the pediatric population of Khabarovsk, the authors developed a method of improved analysis of benign tumor morbidity. The method suggests the use of case histories as well as medical check-up data. Mathematical modelling was employed to compare primary incidence and occurrence indexes. The improved mean incidence of benign tumors in children for 1985-1989 was 66.8 cases and improved occurrence--174.2 per 10,000 children. The values are by the order of magnitude higher than those reported by hospitals.