Backgroundβ‐hydroxybutyrate (BOHB) concentrations have not been quantified in dogs with acute pancreatitis (AP).ObjectiveThe aim of this study was to investigate BOHB concentrations in dogs with AP.AnimalsA total of 154 client‐owned dogs without DM.MethodsProspective clinical study. Dogs were enrolled into 1 of 3 groups: AP, sick without an AP diagnosis, or fasted. Dogs were diagnosed with AP (44) if they had vomiting or anorexia, and either ultrasonographic findings consistent with AP or increased pancreatic lipase. Sick dogs without AP (68) had vomiting or anorexia but a diagnosis of AP was either not suspected or was excluded based on ultrasonographic findings or a normal pancreatic lipase. Dogs without anorexia or vomiting that were fasted for over 10 hours for a procedure were also enrolled (42). BOHB was measured on whole blood with a portable ketone meter. The Kruskal‐Wallis test was performed to compare BOHB in the 3 groups. Pair‐wise comparisons were performed using the Mann‐Whitney test and Bonferroni corrected P‐values are reported.ResultsMedian BOHB concentration was significantly higher in dogs with AP (0.3 mmol/L, range 0–2.9 mmol/L) compared to sick dogs without AP (0.20 mmol/L, range 0–0.9 mmol/L, P = .007) and fasted dogs (0.1 mmol/L, range 0–0.4 mmol/L, P = .0001). Median BOHB concentration was significantly higher in sick dogs without AP compared to fasted dogs (P = .0002).Conclusions and clinical importanceIn dogs without DM, BOHB is significantly higher in dogs with AP compared to other dogs. The diagnostic utility of this finding remains to be investigated.