Project Summary: Diabetes mellitus is one of the most common severe chronic diseases of childhood. However, epidemiological data for temporal trends in childhood diabetes (both type 1 and type 2 diabetes) are limited in the U.S. with the exception of SEARCH for Diabetes in Youth, no comprehensive population-based studies of diabetes according to type in young people of diverse racial or ethnic backgrounds exist. SEARCH is a multi-center and an epidemiological study conducted in six geographically dispersed Study Centers that encompass the racial and ethnic diversity of the U.S. In response to RFA-DP10-001, Component A, we propose the SEARCH for Diabetes in Youth Registry Study. The project proposes 1) to continue to ascertain newly diagnosed (2010-2014) incident diabetes cases in youth age <20 years in order to assess temporal trends in diabetes incidence and temporal trends in presentation of diabetes for the period 2002-2014, by age, sex, race/ethnicity, and diabetes type;and 2) to provide consultation and support to inform the development of low-cost sustainable public health surveillance systems of childhood diabetes in the U.S. The population under surveillance at the Colorado SEARCH Center consists of all youth ages <20 years a) residing in the state of Colorado (63 counties), and b) members of the Navajo Nation American Indian population in Arizona and New Mexico, who participated in SEARCH 1 and 2. Our Center is the largest SEARCH site with over 3000 incident cases registered to date (30% of all SEARCH registered cases) that will inform the analysis of trends in incidence of diabetes in youth. This project builds on the multi-center standardized data collection effort, the experienced investigator team, and the local case ascertainment infrastructure developed by SEARCH-Colorado Center.