in recent years, the number of cases of urban malaria in buenaventura, colombia, has increased, rising from 576 in 1987 to 3296 in 1991 and 2017 in 1992. for this reason, an epidemiologic study to identify malaria transmission patterns was carried out in this municipality on colombia？s pacific coast. this article describes the entomologic findings regarding the vectors, their breeding sites, and the behavior of anopheles species during the period from june 1993 to may 1994. of the 469 potential breeding sites identified in the urban area, 28 were positive for anophelines, while in neighboring zones 20 out of 80 potential breeding sites were positive for the immature forms of these mosquitoes. mining excavations, lakes, and commercial fish and crayfish rearing ponds were the places where a. albimanus was most frequently found. for a. nu？eztovari, the breeding sites were rain puddles and aquiculture ponds. a. neivai larvae were collected from bromeliads. mosquitoes were collected both inside and outside houses, and 90% of the collected mosquitoes were identified as a. albimanus. of the female a. albimanus, 54.8% were parous. this species was found to have peak peridomiciliary activity between 6 p.m. and 10 p.m. the highest biting rate outside houses was 7.1 bites per person-hour and was observed during march. it is hoped that this entomologic information will permit the launching of a strong community participation process and the implementation of control measures that are guided by these results.