OBJECTIVES: To characterize hemodynamic alterations occurring during diabetic ketoacidosis (DKA) in a large cohort of children and to identify clinical and biochemical factors associated with hypertension. STUDY DESIGN: This was a planned secondary analysis of data from the Pediatric Emergency Care Applied Research Network Fluid Therapies Under Investigation in DKA Study, a randomized clinical trial of fluid resuscitation protocols for children in DKA. Hemodynamic data (heart rate, blood pressure) from children with DKA were assessed in comparison with normal values for age and sex. Multivariable statistical modeling was used to explore clinical and laboratory predictors of hypertension. RESULTS: Among 1258 DKA episodes, hypertension was documented at presentation in 154 (12.2%) and developed during DKA treatment in an additional 196 (15.6%), resulting in a total of 350 DKA episodes (27.8%) in which hypertension occurred at some time. Factors associated with hypertension at presentation included more severe acidosis, (lower pH and lower pCO(2)), and stage 2 or 3 acute kidney injury. More severe acidosis and lower Glasgow Coma Scale scores were associated with hypertension occurring at any time during DKA treatment. CONCLUSIONS: Despite dehydration, hypertension occurs in a substantial number of children with DKA. Factors associated with hypertension include greater severity of acidosis, lower pCO(2,) and lower Glasgow Coma Scale scores during DKA treatment, suggesting that hypertension might be centrally mediated.