Abstract: This report summarizes the diagnosis and treatment of presumptive acute canine polyradiculoneuritis (ACP), also known as coonhound paralysis, in a mixed breed dog. ACP is characterized by acute onset, rapidly progressive ascending tetraparesis to tetraplegia with hyporeflexia and occasional facial weakness and hyperesthesia. Exposure to raccoons is a common but not universal antecedent event. The presumptive diagnosis is made by ruling out other causes of neuromuscular disease; no specific confirmatory test is available. Treatment is primarily supportive, and most dogs regain the ability to walk after weeks to months. Complications include respiratory paralysis resulting in death, pneumonia, urinary tract infections, and permanent neurologic or musculoskeletal deficits.