Neoplasms correspond to the large part of routine care of domestic animals, and, among them, lymphoma represents the tumor with the highest incidence in domestic cats. Due to its multifactorial etiology, being influenced by environmental factors and lifestyles of the animals, we raised the hypothesis that exposure to tobacco smoke influences the development of lymphoma in domestic cats. These animals are very close to the guardians, in addition to hygiene habits (grooming), which favors the inhalation of smoke and ingestion of tobacco particles that are deposited in the fur. According to studies, domestic cats exposed to tobacco smoke have higher risks of developing lymphoma when compared to non-exposed cats, and this higher index is directly related to the components found in smoke. Nicotine, cotinine and NNAL(4-(methylnitrosamine)-1-(3-pyridil)-1-butanone) are the main metabolites derived from tobacco and they have been used as urinary biomarkers. Studies show that domestic cats that live in households with the presence of smokers present relevant levels of urinary biomarkers when compared to animals not exposed to environments with smokers. Nicotine levels in animals are directly proportional to the number of cigarettes smoked by guardians and are related to the degree of exposure of animals. Based on epidemiological research, exposure to smoke is related to the emergence of neoplasms in domestic cats similar to that in humans, but it is necessary to develop new research in the veterinary area.