We conducted a survey of the species of frugivorous flies (Tephritidae and Lonchaeidae), their hosts, and their parasitoids found on Ilha de Santana, Amapá State, Brazilian Amazon. We also assessed host plant use by Bactrocera carambolae Drew & Hancock. Fruits were collected from various plant species, at 30 d intervals, from Jan to Jul 2015. In total, 149 fruit samples were collected (3,142 fruits, 76.3 kg), belonging to 20 plant species (9 native and 11 introduced) in 13 botanical families. Infestation by fruit flies was observed in 86 samples (11 species in 8 botanical families). Specimens of 5 species of Tephritidae and 4 species of Lonchaeidae fruit flies were obtained, as well as 3 species of braconid parasitoids. The most important fruit fly species on Ilha de Santana are: B. carambolae, for being a species of quarantine importance; and Anastrepha obliqua (Macquart) and Anastrepha striata Schiner, for infesting plant species of local socioeconomic importance. Averrhoa carambola (Oxalidaceae), Eugenia uniflora (Myrtaceae), Malpighia emarginata (Moc. & Sesse) ex DC. (Malpighiaceae), and Psidium guajava (Myrtaceae) are the host plants responsible for sustaining the population of B. carambolae.