A precipitin test was employed to study the alimentary tract content of Lutzomyia longipalpis in the intra- and peridomiciliary environments in the municipality of Raposa, Maranh o State, a transmission area for visceral leishmaniasis or kala azar. Out of 2,240 female sandflies captured, 547 (24.4%) had fed on vertebrate blood, with the following proportions: avian (87.9%); rodent (47.2%); human (42.4%); canine (27.6%); opossum (26.6%); and equine (22.5%). Based on a survey of 120 human dwellings, chickens were found to be the most common domestic animals in the peridomicile (28.3%), followed by dogs (21.7%), cats (17.5%), donkeys (13.3%), pigeons (7.5%), rabbits (3.3%), ducks (3.3%), and horses, mallards, and pigs (1.7% each). Synanthropic animals included opossums (39.3%), followed by rats (37.9%), bats (14.3%), raccoons (3.6%), foxes (2.1%), snakes (1.4%), and frogs (1.4%). The peridomiciliary presence of domestic and synanthropic animals as well as sandflies that had fed on human, opossum, and canid blood supports the hypothesis that kala azar transmission has been taking place in the anthropic environment in the municipality of Raposa.