AIMS: To study the cumulative incidence of hospitalization for severe diabetic vascular complications in childhood onset type 1 diabetes patients with special regards to age at onset and gender. METHODS: The Swedish Childhood Diabetes Register (SCDR) was linked to the Swedish Hospital Discharge Register up to 31 December 2004. The following diagnoses were traced: diabetic kidney disease, myocardial infarction, stroke, lower limb arterial disease and diabetes with multiple complications. Cox proportional hazards survival method was applied with the following covariates: maternal age, birthweight deviation from gestational week standard, age at onset and gender. RESULTS: Until 31 December 9974 children had been followed for at least 10 years corresponding to 141 839 person years at risk and 103 (7.3 per 1000 person years) had been hospitalized at least once at the maximum duration of follow-up of 26 years. Diabetic kidney disease was the most common cause of hospitalization and 63 patients had more than one diabetic complication. Female gender (RR=2.02, 95% CI=1.05-3.89) and age at onset of diabetes (RR=1.37, 95% CI=1.20-1.56) were significant risk factors for severe complication. CONCLUSIONS: Hospitalization for severe diabetic complications at a maximum follow-up of 26 years is rather low in Sweden. There is a higher hospitalization rate among females than among males, and also among patients diagnosed with diabetes after 10 years of age than among patients diagnosed before the age of 10 years.