A IO month-old male intact pit bull terrier presented to the Humane Society of Cozumel for two episodes described as seizures. He was adopted off the streets as a puppy and had no histmy of vaccinations. Upon presentation he had prominent myoclonus affecting the left hind limb, nasal hyperkeratosis, and nasal and ocular discharge. Due to a high index of suspicion for canine distemper virus (CDV) infection, a CDV Ag Rapid Test Kit was performed, yielding a positive result. Due to a poor prognosis, the patient was euthanized. This case was part of an ongoing outbreak ofCDVon the island of Cozumel, Mexico, starting on Januaiy 10, 2017. The Humane Society of Cozumel began seeing dogs with CDV ranging in age from weeks to years, most commonly affecting puppies. These animals presented with a range of signs including fever, respiratory signs, gastrointestinal signs, neurologic signs, and hyperkeratosis of the nose and footpads. They had a history ofno vaccinations or rabies vaccination only. CDV has been an ongoing problem on the island of Cozumel. While the cause of the outbreaks is unclear, the lack of vaccination against CDV, the enclosed island geography, and the presence of wildlife hosts are likely perpetuating the recurrent outbreaks. This report will discuss the clinical signs, diagnosis, treatment, and epidemiologic concerns of CDV.