The objective of this study was to evaluate retrospectively demographic and clinicopathologic factors that may be associated with the diagnosis and outcome of acute renal failure (ARF) in dogs presented to a large referral hospital. Medical records of dogs presented to the hospital were searched for a diagnosis of ARF. The diagnosis of ARF was based on clinical signs, renal imaging findings, and clinicopathologic data and, in most cases, was confirmed by histopathology, prior serum creatinine concentrations, response to therapy, and known recent nephrotoxin exposure or ischemic event. Demographics, selected clinicopathologic findings, and concurrent disorders that may have been associated with development of ARF were extracted from these records. A reference population was derived from 481 dogs presenting to the same hospital. Demographic data also were collected from these medical records. The demographic factors associated with a diagnosis of ARF and the factors associated with outcome of ARF were assessed by reviewing a series of multiple logistic regression models. Conclusions from this study were as follows: (1) Intact male dogs and nonsporting dogs were more likely to develop ARF and be admitted to the teaching hospital. (2) Dogs with severe azotemia (serum creatinine concentration > 10 mg/dL), hypocalcemia (<8.6 mg/ dL), and proteinuria were less likely to survive ARF and be discharged from the hospital. (3) Dogs that survived in the hospital for more than 5 days were more likely to recover and be discharged from the hospital.