This paper discusses a fatal illness of unknown etiology in a red kangaroo, Macropus rufus. The animal's initial clinical presentation was suggestive of an esophageal obstruction. Diagnostic imaging and surgery failed to reveal a gastrointestinal lesion. The animal's blood tests and the appearance of new clinical signs indicated dysfunction in multiple organ systems, with progression of the disease despite supportive care. Clinicians made a presumptive diagnosis of toxoplasmosis and started antimicrobial treatment. The animal's condition continued to decline, and it died 8 days after the onset of clinical signs. Necropsy results were inconclusive but suggested impaired esophageal motility. An initial histopathologic diagnosis of toxoplasmosis was later questioned, but a definitive diagnosis has not been made. This paper suggests that the animal's illness was the consequence of peri-anesthetic complications related to a chemical immobilization that occurred 6 days prior to the onset of clinical signs.