Feline cytauxzoonosis is a disease caused by Cytauxzoon felis, a protozoan that infects the red blood cells and macrophages. It is responsible for an acute and often fatal disease in domestic cats. The purpose of this study was to investigate the occurrence of C. felis infections in healthy cats. Piroplasm forms were seen in the erythrocytes of 2 cats, and C. felis DNA was identified by polymerase chain reaction (PCR) in one of them. The results demonstrate that erythrocytic piroplasmids associated with tick-borne parasitic protozoa may be found circulating in the blood of healthy cats in Rio de Janeiro. These can be differentiated from the morphologically similar forms of species such as Babesia by analysis of DNA, thereby demonstrating the potential for further studies of feline populations in Brazil.