The organophosphorous (OP) pesticide fenthion is widely used in commercial fruit industry and orchards in South America. Among the metabolic effects in mammals caused by fenthion, hyperglycemia occurs via the activation of hepatic metabolic pathways, which may interfere with the function of several organs and systems. The purpose of this study was to evaluate the effects of acute and sub-chronic levels of fenthion on energy metabolism and liver morphology of frugivorous bats (Artibeus lituratus), which usually feed on fruits cultivated on South American plantations where fenthion is used. Animals were fed fruit treated with fenthion by immersion of fruit in a solution containing fenthion (500 ppm) and an adhesive spreader (200 ppm). Blood glucose levels did not change due to fenthion treatment, but muscle glycogen content increased and carcass fatty acids decreased after acute exposure. An increase in hepatocyte cell diameter further characterized as an increase in vacuolization was observed. The results indicate that fenthion may affect some components of energy metabolism and promote alterations in hepatocyte morphology in frugivorous bats when applied to cultivated fruits at the recommended rates.