The association between the prevalence of infestation by Rhipicephalus sanguineus and Ctenocephalides felis felis and the presence of anti-Leishmania antibodies has been evaluated in dogs located in a city of Brazil endemic for canine visceral leishmaniasis. Blood samples from 5556 domestic dogs domiciliated in the urban area of Belo Horizonte (Minas Gerais state) were submitted to enzyme linked immunosorbent (ELISA) and indirect immunofluorescent antibody (IFAT) assays, and 432 (7.8%) animals tested positive. Seropositive (n = 200) and seronegative (n = 200) dogs were randomly selected and examined for the presence of ticks and fleas, the results of which were expressed qualitatively as infested or non-infested, irrespective of the intensity of infestation. The prevalence of infestation by R. sanguineus was significantly greater (ρ = 0.04) among seropositive dogs (38.5%) compared with their seronegative counterparts (29.0%). Similarly, the prevalence of infestation by C. felis felis was significantly greater (ρ < 0.01) within the seropositive group (36.5%) than within the seronegative group (15.0%). Moreover, the probability of seropositivity for Leishmania was 53% higher in tick-infested dogs and 300% higher in flea-infested dogs in comparison with non-infested animals. Our data provide evidence of the vectorial capacity of these ectoparasites in transmitting Leishmania to the canine population, although further studies are needed to confirm or reject this hypothesis.