© Güncel Pediatri Dergisi, Galenos Yayınevi tarafından basılmıştır.Introduction: Diabetic ketoacidosis (DKA) is a serious result of insulin deficiency and cause serious mortality and morbidity in children with type 1 diabetes mellitus (DM). Retrospective evaluation of DKA cases is of importance in terms of the evaluation of responses to treatment and reducing the complications. Materials and Methods: A total of 412 DKA attacks of 379 patients, who were treated with the diagnosis DKA in Uludağ University Faculty of Medicine Department of Child Endocrinology between the dates 01.01.1997 and 15.11.2012, were retrospectively examined. Those who were not diagnosed before applying were named as new diagnosis type 1 DM; and those who were diagnosed with type 1 DM before were named as old type 1 DM. Results: While the median symptom time in new diagnosis type 1 DM group is 14 days and the most frequent symptoms are polyuria, polydipsia and weight loss; and the median symptom time in old diagnosis type 1 DM group is 2 days and the most frequent symptoms are vomiting, polyuria and polydipsia. The most frequent DKA causes in old diagnosis type 1 DM Group are; skipping insulin dose (58.6%) and not following the diet (56%). Within a period of 15 years, 2 ptients in new diagnosis type 1 DM group died due to cerebral edema and related complications. Conclusions: DDKA is the most important complication of type 1 DM and the main reason of type 1 DM related deaths. DKA development can be reduced by training parents on the fact that symptoms like polyuria, polydipsia and weight loss, may be symptoms of type 1 DM. Particular attention shall be paid for younger age group because the most severe DKA is observed between 0-5 years of age.