An eighteen month old female spayed English Mastiff presented with anorexia, weight loss, regurgitation, and ataxia. On examination, the dog was ataxic in the pelvic limbs with absent patellar reflexes and diminished withdrawals. Megaesophagus with secondary aspiration pneumonia was present. A presumptive diagnosis of generalized neuromuscular disease was made. On necropsy, a mononuclear infiltrate was present in the spinal ganglia with secondary degeneration of the dorsal funiculus of the spinal cord. No specific etiologic agent was identified and the necropsy findings are similar to previously reported cases of ganglioradiculitis or sensory neuropathy.