Improvements in veterinary medicine have resulted in a significant benefit in the life of pets in the last 20 years, and increased pet life expectancy led to an increased prevalence of canine neoplasia. Cancer epidemiology and spatial analysis tools, although well developed for human oncology research, is just beginning to be explored in veterinary oncology. São Paulo city, capital of the state of São Paulo, Brazil, is divided into five regions: North, South, East, West and downtown. The Veterinary Hospital of the School of Veterinary Medicine and Animal Science, University of São Paulo (HOVET-SVMAS-USP), is located in the West region of São Paulo, Brazil, and admits cases of small and large animals. Canine mammary tumors are so numerous that they are not routinely treated at the HOVET. The aim of this work was to perform a cartographic study to describe the spatial distribution of prevalent cases of neoplasms in dogs from the HOVET. Of the 3,620 cases seen in 2002 and 2003, 380 cases (10.5%) were of dogs affected with benign and malignant neoplasms. No statistical difference was found for the 380 addresses distributed among the five regions of the city. These results showed that the HOVET receives canine patients from all regions of São Paulo and there is a homogeneous spatial distribution of neoplasms. Authors encourage additional broader studies, involving several veterinary hospitals, clinics or laboratories in order to obtain more accurate data on distribution of canine neoplasms in São Paulo, SP, Brazil.