To determine the incidence and examine temporal trends of Type 1 diabetes among children aged < 18 years, in a large Israeli health organization. All incident Type 1 diabetes cases diagnosed between 2000 and 2008 were ascertained from an automated diabetes registry based on members' electronic records and validated by comparison with the Israel Juvenile Diabetes Register. During the study period, a total of 648 incident cases of Type 1 diabetes were identified. The average annual age-and-sex-standardized incidence was 11.09 per 100,000 person-years. There was an annual 5.82% (95% CI 1.80-9.98%) rise in incidence, with a greater relative increase in toddlers under 5 years of age. Incidence increased with age and demonstrated seasonal variation. Mean age at onset of diabetes significantly (P = 0.07) decreased from 10.21 years (SD = 4.48) in 2000-2002 to 9.25 years (SD = 4.54) in 2006-2008. Among very young patients (< 5 years), average blood glucose values at diagnosis dropped from 32.4 mmol/l (SD = 9.5) to 19.5 mmol/l (SD = 11.0) over the study period, with little change in average glucose for older children. Incidence of diagnosed Type 1 diabetes continues to increase in Israel at a rate that is high compared with similar American and European populations. At the same time, the clinical presentation of children is changing. © 2010 The Authors. Diabetic Medicine © 2010 Diabetes UK.