The study was developed in the neighborhood of Residencial Paraíso, São Luis, Maranhão, Brazil, from 1999 to 2001. The aim was to analyze the epidemiological aspects of malaria. The location is receptive and vulnerable to malaria. There were 129 cases. Men from 20 to 29 years of age were most involved. Plasmodium vivax was the agent of all cases and Anopheles aquasalis was the vector. There was no evidence of transmission occurring outside of the houses.