The proposed research is designed to test the hypotheses: 1. There is no geographic variation in the incidence of childhood diabetes in China. 2. There is no evidence for ethnic group variation in the incidence of childhood diabetes in China. 3. There is no evidence for temporal variation in the incidence childhood diabetes in China. To test these hypotheses we will establish 13 population based childhood diabetes registries in China according to the standards we have developed in our WHO Multinational Project for Childhood Diabetes (Diabetes Mondiale, DiaMond). The total population base is 23,827,000 children aged 0-14. The duration of the registry is 1990-95. The research is significant as 1) China appears to have an incidence 1/150 to 1/40 that of the U.S. 2) The remarkable ethnic diversity could suggest major incidence differences even in this very low risk country, and 3) the major environmental differences and changes over time would predict evidence of epidemics, and it is in the epidemics that the diabetogenic agents causing diabetes will be found. If one or more of the hypotheses is rejected then we would potentially plan to expand our efforts to immunogenetic studies to determine if the geographic variation was the result of differences in host susceptibility, outbreak investigations to identify the factors responsible for childhood diabetes epidemics and migrant studies investigating Chinese heritage groups living in the U.S., Hong Kong, Taiwan, and Singapore.