To determine the efficacy and acceptability of deltamethrin-impregnated bednets in controlling Chagas disease in South America. In three endemic departments of Colombia, a qualitative study on people's knowledge about Chagas disease, vectors, preventive measures and their willingness for collaboration in control operations was undertaken. Additionally, in an entomological study with 100 laboratory-bred Chagas vectors (Rhodnius prolixus), vectors were released for 5 nights (20 each night) in an experimental room, with the human bait protected for one night by an unimpregnated and for four nights by a deltamethrin-impregnated bednet (13 mg/m2). Vectors were stained with fluorescent powder for observation, collected after 10 h exposure in the experimental room and observed for a further 72 h. The study population did not know anything about Chagas disease, but believed the vector to transmit cutaneous leishmaniasis. Therefore willingness to take part in control operations was high. The experimental hut study showed a vector mortality rate of 95% in a room with impregnated nets and of 10% in a room with unimpregnated nets. This study opens a new perspective for Chagas disease control in integrated vector borne disease prevention programmes.