Background: Diabetic ketoacidosis (DKA) is an acute complication of pediatric type 1 diabetes mellitus (T1DM). We aimed to determine the risk factors and clinical characteristics of children and adolescents with DKA. Methods: We retrospectively evaluated 59 episodes of DKA in 43 patients who were hospitalized for DKA between January 2006 and December 2015. DKA was classified as mild, moderate, or severe, according to patient history of DKA. The clinical and laboratory characteristics of these subgroups were compared. Results: The average patient age was 11.98 ± 4.40 years (range, 1.3~17.9 years). Moderate episodes were the most common, with 21 episodes (35.6%), followed by 19 severe (32.2%) and 19 mild episodes (32.2%). Significant differences were observed between the subgroups regarding their characteristics of aggravated. Severe DKA episodes were more often observed during the winter season. Recurrent DKA cases were determined in 31 episodes (52.5%) who were significantly older, had higher body mass index, and lower serum C-peptide levels than the newly diagnosed DKA group. Female patients experienced severe and moderate cases more frequently (P = 0.041), which included two deaths. Only blood glucoseCorresponding author: Min Sun Kim Department of Pediatrics, Chonbuk National University Hospital, 20 Geonji-ro, Deokjin-gu, Jeonju 54907, Korea, E-mail: children@jbnu.ac.kr Received: Feb. 20, 2017; Revised: Jun. 5, 2017; Accepted: Jul. 18, 2017 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.