Background: Diabetic ketoacidosis (DKA) is a late presentation of newly diagnosed type 1 diabetes mellitus (DM) in children. The aim of this study was to determine the clinical characteristics of type 1 DM at presentation so that appropriate actions can be taken to promote early diagnosis. Methods: This was a retrospective cohort review from a patient registry database. Data on all patients younger than 20 years old diagnosed with type 1 DM who had been registered with the Malaysian Diabetes in Children and Adolescents Registry (DiCARE) from its inception in 2006 until 2009 were analysed. Results: The study included 490 children and adolescents, out of which 57.1% were female. The mean (SD) age at diagnosis was 7.5 (3.7) years, which increased from year 2000 to 2009 [6.6 (3.3) years to 9.6 (3.5) years; p = 0.001]. An increasing percentage of DKA at diagnosis was observed from year 2000 (54.5%) to year 2009 (66.7%), which remained high and leveled between 54.5% and 75.0%. DKA was more common in patients with normal weight (p = 0.002) with no significant association with age, gender, ethnicity and status of family history of diabetes mellitus. Conclusion: An increasing trend of age at diagnosis of patients with type 1 DM was observed. Besides that, proportion of DKA at diagnosis had remained high over the past decade. This study found that normal weight was associated with status of DKA, thus more detailed investigations are required to determine the risk factors for DKA.