ABSTRACT.- Thorough and systematic surveys of host associations of Anastrepha fraterculus and Ceratitis capitata are lacking in Uruguay. Our aim was to establish the host status in field conditions and the pattern of use of different fruit species in agroecosystems and wild environments in Uruguay. Tephritid monitoring was conducted in citrus and deciduous fruit orchards using McPhail traps baited with four PBX® yeast/borax pellets. A survey of host fruits was conducted by collecting fruits in commercial and non-commercial orchards and wild vegetation. Ceratitis capitata and A. fraterculus were the only two economically important fruit fly species recorded. Ceratitis capitata prevailed in citrus groves and deciduous fruit orchards associated with commercial and disturbed environments whereas A. fraterculus was associated mostly with non-commercial fruits and undisturbed ecosystems. The differences in abundance of C. capitata and A. fraterculus observed in different hosts and ecosystems may be related to factors such as host association, resource competition, environmental conditions and parasitism, among others that are discussed. © 2022 Informa UK Limited, trading as Taylor & Francis Group