Transmissible venereal tumor (TVT) is a contagious, sexually transmitted tumor and, in the natural setting, affects only dogs. We surveyed two cases which were serviced in veterinary medical teaching hospital of Seoul National University. Through this report we studied the method for treatment or n by chemotherapy and surgical resection. in treatment or TVT, surgical resection is not considered an effective method, but chemotherapy and radiation. In these two cases, chemotherapy was very effective and in the second case, there was no effect of surgical method. For treatment of TVT, chemotherapy was very effective, but surgical resection was not recommended.