A comprehensive classification accounting for the heterogeneity of pediatric diabetes is lacking. The Aβ classification system, based on islet autoantibody status (A+ or A-) and preserved beta-cell functional reserve (β+ or β-) , was used successfully to define variable phenotypes in adults with Ketosis-prone Diabetes. We set out to investigate the utility of the Aβ classification system in children with new-onset diabetes. “A+” was defined as the presence of ≥1 islet autoantibodies (GAD65, ICA512, insulin or ZnT8 autoantibodies) and "β+" as random C-peptide level ≥0.6 ng/mL at diagnosis. We calculated T1D genetic risk score 2 (T1D GRS2) for each participant, and compared clinical characteristics at diabetes onset and T1D GRS2 between the groups. The study cohort (n=76) was 50% female, 29% non-Hispanic white, 46% Hispanic, 22% non-Hispanic black, and 3% Other. The mean age was 11.7 years and the mean BMI was 58.3%ile. Aβ classification at diagnosis defined the following groups: A+β- (34%) , A+β+ (30%) , A-β+ (33%) and A-β+ (3%) . Results are summarized in Table 1. The Aβ classification system defines phenotypically and genetically distinct diabetes groups in children with new-onset diabetes. This classification system may be useful in clinical settings as well as the design of clinical trials. Disclosure M.Tosur: Advisory Panel; Provention Bio, Inc. S.Deen: None. S.Uysal: n/a. M.Astudillo: None. F.Jahoor: None. W.Hagopian: Research Support; Janssen Research & Development, LLC. R.A.Oram: Consultant; Janssen Research & Development, LLC, Research Support; Randox R & D. M.J.Redondo: Advisory Panel; Provention Bio, Inc. A.Balasubramanyam: None. Funding Texas Children's Pilot Award