Papillomaviruses can infect epithelia and induce proliferative disorders. Different types of canine papillomaviruses have been found to be associated with distinct pathologies including exophytic warts as in canine oral papillomatosis, endophytic warts, and pigmented plaques and, in some cases, squamous cell carcinomas. Virus infection is followed by a phase of subclinical infection before the onset of symptoms. A diagnosis can in some cases be made clinically but should be verified if there are any doubts. Most papillomas do regress spontaneously within a few months. Preventative vaccination is possible but not on the market.