OBJECTIVE: The incidence of type 1 diabetes varied in different countries, different nations and different regions. This survey was conducted to clarify the incidence of type 1 diabetes of children in Beijing area between 1997 and 2000, to compare and analyze the difference in incidence of type 1 diabetes between the 2 periods of 1988 - 1996 and 1997 - 2000. METHOD: According to the criteria of WHO Diabetes Mondial (DIAMOND), data were collected from all the children younger than 15 years of age in Beijing area who had the onset of type 1 diabetes during Jan. 1st, 1997 to Dec. 31st, 2000. Using the capture-recapture methods, 95% confidence intervals of incidence were calculated with Poisson's distribution formula. The significance of differences was tested with Chi-square method. RESULTS: The incidences of type 1 diabetes during 1997 - 2000 were around 0.76/100 000 to 1.21/100 000. The average yearly incidence was 1.014/100 000 (95% confidence interval was 0.98/100 000 - 1.16/100 000). There was no significant difference in the incidence between 1988 - 1996 and 1997 - 2000, and it showed the same result when the incidences were adjusted by age according to the Chinese population census in 2000 (The incidence was 0.83/100 000 in 1988 - 1996 and 0.86/100 000 in 1997 - 2000, respectively). The incidence was higher in 10 - 14 year-old group than the younger groups (P = 0.002). There was no significant difference between male and female groups, either. CONCLUSIONS: No significant difference was found between the periods 1988 - 1996 and 1997 - 2000 when the average yearly incidence of type 1 diabetes of children in Beijing was compared. These results were different from the other countries' reports that the incidence of type 1 diabetes was increasing by 3% - 5% per annum. There was no significant difference between male and female groups either and there was a higher incidence of type 1 diabetes in 10 - 14 yr group than the other groups in 1997 - 2000. Although the life-style of Beijing people changed a lot, it didn't affect the incidence of type 1 diabetes in children in this area. But since many people migrated to Beijing from other parts of the country, the changes in constitutive proportions of population might have some impacts on the results of the survey.