Background: Hyperlipasemia is frequent in critically ill people without evidence of acute pancreatitis (AP), and has been associated with increased morbidity and mortality. Objective: To evaluate the prevalence of hyperlipasemia at admission and development of hyperlipasemia during hospitalization in critically ill dogs, explore factors associated with hyperlipasemia, and evaluate association with outcome. Animals: Critically ill, client owned dogs (n = 1360), presented on emergency and admitted to the intensive care unit, that had 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6 0-methylresorufin) ester (DGGR) lipase activity measured within 24 hours of admission. Methods: Retrospective cross-sectional study of clinical and laboratory records. Results: The DGGR lipase activity was increased >3× the upper reference limit at admission in 216/1360 (16%) dogs, of which 70/216 (32%) had a clinical diagnosis of AP. Other primary conditions associated with hyperlipasemia were renal, endocrine, and immune-mediated diseases, and upper airway obstruction. Predictors of hyperlipasemia at admission were prior glucocorticoid administration, vomiting and abdominal pain, increased age, plasma bilirubin and creatinine concentrations, and decreased hematocrit. Of dogs with repeat measurements, 78/345 (23%) had significantly increased lipase during hospitalization, of which 13/78 (17%) had a clinical diagnosis of AP. Other primary conditions associated with in-hospital hyperlipasemia were renal and immune-mediated disorders.