Background: The incidence of type 1 diabetes mellitus (T1DM) is increasing rapidly worldwide for children of every age group. Materials and Methods: A retrospective analysis of hospital registration data from five tertiary hospitals in Beijing, China, identified 485 patients (210 boys, 275 girls) younger than 15 years of age with newly diagnosed T1DM between 1995 and 2010. Results: From 1995 to 2010, the incidence of T1DM in patients <15 years of age ranged from 0.935-3.26 per 100,000 per year. During this period, the average age-standardized incidence rate was 1.7 per 100,000 per year, and the average annual increase in T1DM incidence was 4.36%. The highest rate increases occurred in boys and in patients <5 years of age. For both genders and all age groups, T1DM incidence increased at an accelerated rate after 2006. By 2020, the incidence of T1DM among children in Beijing is projected to increase by a factor of 1.69. Conclusions: The incidence of T1DM among patients younger than 15 years of age in Beijing increased from 1995 to 2010, with rates growing at an accelerated pace since 2006. Based on recent trends, we project continued rapid growth in the number of new childhood T1DM cases in Beijing.