Background: Sporotrichosis is an endemic zoonosis in the metropolitan region of Rio de Janeiro caused by fungi included in the Sporothrix complex, in which cats are the main source of infection for humans and animals. Coinfections in cats with sporotrichosis from this region, their risk factors and how they affect the treatment outcome in these animals are little known. The objectives of this study were to determine the coinfections of Sporothrix spp. with Toxoplasma gondii, Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) and to correlate these infections with risk factors and the outcome of sporotrichosis treatment in cats from an endemic area of sporotrichosis in Rio de Janeiro, Brazil. Materials, Methods & Results: It was conducted a cohort study involving 213 cats with definitive diagnosis of sporotrichosis from the metropolitan area of Rio de Janeiro and assisted in the Laboratory of Clinical Research on Dermatozoonosis in Domestic Animals (LAPCLIN-DERMZOO)/Evandro Chagas National Institute of Infectious Diseases (INI)/Oswaldo Cruz Foundation (Fiocruz), in Rio de Janeiro, RJ, Brazil, from November 2007 until February 2011. These animals were monthly evaluated due to sporotrichosis treatment until their sporotrichosis treatment outcomes. In every clinical evaluation, 5 mL of blood were collected in order to obtain the serum, which was stored at -20ºC. Information from the animal’s medical records have also been collected, such as sex, eating habits, living with other cats, access to the streets, castration, age and the outcome of sporotrichosis treatment. Serological follow-up of anti-T. gondii antibodies were performed through indirect hemagglutination assay (IHA) and indirect fluorescent antibody test (IFAT) in all clinical evaluations. The FIV and FeLV antibody detection were made through a rapid immunoassay using the cats’serum samples from the first clinical evaluation. Fisher’s exact test was applied to verify associations between T. gondii, FIV and FeLV coinfections, the outcome of sporotrichosis treatment and risk factors. To compare IHA and IFAT, the values of total, positive and negative concordances were evaluated. A P-value < 0.05 indicated significant associations in the statistical tests. Of the 213 cats, fourteen (6.6%) showed antibodies anti-T. gondii, twelve (5.6%) anti-FIV and thirty-five (16.4%) anti-FeLV. There was a concordance of 100% between IFAT and IHA for the serological diagnosis of T. gondii infection. No statistical difference was observed between the presence of anti-T gondii antibodies with the FIV and FeLV infections and with the outcome of sporotrichosis treatment (P > 0.05). Furthermore there was no significant statistical difference between the presence of anti-T gondii antibodies and the variables sex, eating habits, living with other cats, free access to the street, castration and age (P > 0.05). The follow-up of anti-T.gondii antibodies showed that in two cats there was a fourfold rise in the titers between two consecutive follow-ups and in one there was seroconversion, which were indicative of acute infection. Discussion: The occurrence of coinfections of sporotrichosis with T. gondii, FIV and FeLV was low in cats from the metropolitan region of Rio de Janeiro, Brazil, where sporotrichosis is endemic. This was the first study that determine and follow-up the frequency of anti- T. gondii antibodies in a group of cats diagnosed with sporotrichosis. The fact that cats were domiciled with adequate feeding and management, the low frequency of T. gondii and the rare cases indicative of acute infection in the study population indicate that these animals are not highly exposed to infection by this protozoan.