OBJECTIVE: We aimed at analyzing the frequency, clinical characteristics, and trends associated with the occurrence of diabetic ketoacidosis (DKA) at the onset of type 1 diabetes on the basis of long-term follow-up data. RESEARCH DESIGN AND METHODS: A total of 106 pediatric diabetes centers in Germany and Austria participated in this study. Data from 14,664 patients with type 1 diabetes collected between 1995 and 2007 were suitable for evaluation. DKA was defined and classified according to the International Society for Pediatric and Adolescent Diabetes consensus guidelines. RESULTS: DKA was observed in 21.1% of patients. The frequency of DKA, including the severe form, remained unchanged throughout the 13-year observation period. The frequency of DKA was particularly striking among children <5 years of age (26.5%). CONCLUSIONS: Ketoacidosis occurring at diabetes onset continues to be a difficult problem. Our data show no significant change in the frequency and magnitude of DKA over the last 13 years.