This study tested the efficacy of liquid Fipronil (1.0%) against Triatoma infestans, administered by pouring on birds and mammals both in laboratory and field conditions. In the laboratory a chicken, dog, and goat were treated with Fipronil, after which deltamethrin-resistant stage III T. infestans nymphs were fed on them. The control group used same-stage nymphs reared in laboratory. During the field phase, Fipronil was used to treat 4 dogs, 1 cat, and 2 broody hens. Intradomiciliary infestation was treated using aerothermics. In laboratory, nymphal mortality was 100.0% after 7 days and 88.8% after 30 days. In the field, there was a 65.4% decrease in the triatomine density rate after 30 days.