"Tucker" Gold, a four-month-old intact male Bull Mastiff puppy, presented to the Emergency Service of the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania on September 2, 2003 with a twenty-four hour history of trismus, risus sardonicus, difficulty standing, trembling, and dysphagia. A diagnosis of tetanus was made based on history and clinical signs. Despite progression to generalized tetanus and complications due to acute upper airway obstruction and pneumonia, Tucker improved with medical treatment and intensive nursing care. A rare and potentially fatal disease, tetanus is caused by the neurotoxin tetanospasmin produced by Clostridium tetani. This paper will discuss the etiology, pathogenesis, diagnosis, treatment and a case presentation of tetanus.