Chagas disease is endemic to the Americas and is transmitted by blood-feeding kissing bugs. We evaluated the insecticidal potential of a fungus (Beauveria bassiana strain Pr-11) against Triatoma infestans, an important vector in South America. This fungal species was isolated from a locust (Schistocerca piceifrons) that inhabits the Central Andes region of Peru. Ten days post inoculation, this strain induced high insect mortality (97%) at low fungal concentrations (2 × 107 conidia/ml) at 70% relative humidity. The Pr-11 strain outperformed reference strain CCBLE-216 B. bassiana, provided by the Peruvian Ministry of Agriculture. Our results are consistent with previous reports on the virulence of this fungal strain against other insect pests. This is the first study to evaluate an orthopteran-isolated B. bassiana to control Chagas disease vectors. We conclude that strain Beauveria bassiana Pr-11 is effective against Triatoma infestans, resulting in a promising tool to control Chagas disease in Peru and may be used in integrated vector control programs.