ABSTRACT: Feline leishmaniosis is infrequent worldwide, and cats have been suggested as secondary reservoirs for the parasite. However, specific diagnostic techniques for feline samples are scarce. In this study, we standardized an in-house indirect enzyme-linked immunosorbent assay (ELISA) using crude Leishmaniainfantum antigen to detect antibodies in feline samples from an endemic canine visceral leishmaniosis (CVL) area in the western border of Brazil. The results were compared with those of an indirect immunofluorescence assay (IFA). We tested semi-domiciled felines residing in Uruguaiana and Barra do Quaraí, Rio Grande do Sul. Among the 41 samples, 25 (61%) were positive using ELISA and 24 (58%) were positive using IFA (1:40). Our findings demonstrated a high seropositivity of feline samples from the endemic CVL area in the western border of Brazil, and we proposed the use of an in-house ELISA with crude antigen for population screening. This is the first serological survey on felines in a region where CVL is well established.