Phyllonycteris poeyi is endemic to Cuba and Hispaniola in the Greater Antilles, and it is among the most common and widespread bats of the Cuban archipelago. This species is an obligate cave dweller and forms the largest aggregations of bats found in Cuban caves; and could be considered a hot cave specialist. This high gregariousness could increase intraspecific competition of food resources. In this study, we examined the diet of P. poeyi at Cueva de los Majáes located in Baconao Biosphere Reserve in the southeastern region of Cuba. We hypothesized sexual diet variation as a way to reduce intraspecific competition. We estimated the percentage volume and frequency of occurrence of different food categories consumed by both sexes, using faecal analysis. Throughout the year, the diet of P. poeyi is a combination of fruits, pollen and insects; fruits of at least 17 plant species and flowers of five species are used by P. poeyi and the most frequent items were pollen of Roystonea regia and fruits of Piper aduncum and Piper umbellata. Insects occurred in the faeces of both sexes and their frequency and volume were low and did not differ between sexes. Although both sexes fed on similar food categories, we found significant variation in diet composition between sexes. Throughout the year, the majority of females mainly consumed fruits while males had preference for floral resources. We did not find differences in the sexes-reproductive season interaction, therefore the differences could not be attributed to changes associated to reproduction energetics. The average volume of fruits and pollen consumed by females were independent of the reproductive season, only significant differences were found in the consumption of insects, being the highest during the reproductive season. We conclude that this dietary partitioning behaviour between sexes of P. poeyi may be a strategy to maintain a high year-round gregariousness that could be critical to the viability of their large colonies in Cuban caves.