Some species of Lonchaeidae (Diptera) are considered frugivorous and polyphagous pests, and are widely distributed in Neotropical regions. The relationship between a fly and its host plant is important for studies on behavior and distribution of frugivorous flies. The objective of this work was to identify the Lonchaeidae fly species and their host plants in the Cerrado biome, specifically in the state of Piauí, Brazil. Eighty-one adults (33 ♀ and 48 ♂) from the genus Neosilba McAlpine (Lonchaeidae), represented by the species Neosilba inesperata Strikis & Prado, Neosilba pendula Bezzi, and Neosilba zadolicha McAlpine, were collected from fruit samples. Oranges [Citrus sinensis (L.) Osbeck] and guava (Psidium guajava L.) had the highest frequencies of infestation. A Neosilba species was considered a primary invader in orange. These results are the first ones reported of Lonchaeidae species and their host plants in the state of Piauí.