The aim of this paper is to show a case of transmissible venereal tumor (TVT) in a mongrel dog. Physical examination, imaging and histopathologic diagnosis was made. On physical examination, he presented bulge in the front of the head and mouth ulceration; in imaging, it was found vomer bone slightly off and obstructed nasal turbinates; in histopathologicalo, TVT cancer cells were found. Was administered treatment Vincristine Sulfate for 5 weeks, at doses of 0023 mg / kg (3.7 ml) every 7 days for four cycles (with each period of treatment followed by a recovery period), however the last cycle decided to administer a dose of 0.028 mg / kg (5.7 ml). In conclusion, the animal showed no improvement in reducing the tumor mass by 80% in the fifth week of treatment.
