The Pet market can be considered big, as well, indicates strong growth. Between 2011 and 2016, this market grew 6.9 billion of Real, which generates a great motivation to invest in initiatives in this sector. This work proposes the use of a multicriteria methodology for the selection of sites for the installation of a pet shop and expansion of its network, based on decision factors relevant to the southern zone of the city of Rio de Janeiro. The use of this methodology encompasses, considers and weighs the criteria in an aggregate way, being strategic and market oriented, such as: potential of demands, local competitors and their scope of action, flow of people / customers, as well as customer profiles and their needs, so that all factors can be considered in the decision making of the location of commercial points for expansion of Pet shops and veterinary. Aspects related to the location of service and retail units and infrastructure facilities in competitive environments were raised and studied, as well as the main decision models of the two traditional schools in this field, those of the European school (ELECTRE methods and PROMÉTHEE methods) , and those of the American school (methods: MAUT, AHP and MACBETH). In addition to these models, others, such as SAW (Simple Additive Weighting), which do not belong to the two schools, and was the most used method from 2003 to 2013 for decisionmaking with regard to retail location installation selection, also was studied, including this one, was the chosen model for the accomplishment of this work. Also analyzed in the study was a case of implanting the model for the drugstore market, encompassing the sale of products and services at the point of sale. The result obtained was a ranking of possible localities for the installation of commercial points of Pet shops and Veterinary, considering the criteria, adopted weights and final marks assigned to each neighborhood.