ABSTRACT.- Two trials were done, one to evaluate SIT effectiveness to control Uruguayan medfly populations, and another to evaluate the medfly catches in two mass trapping layouts. First, in an 18 ha plot of 'Cripps pink' apple 756,000 sterile males of Ceratitis capitata were released from February to March in 2020, and 990,000 from February to April in 2021. Simultaneously, three 4 ha plots with mass trapping were evaluated as controls. The average sterile:wild ratio in Jackson traps was 13.2 and no differences were found in fruit damage. The second trial consisted in three plots of 1 ha of 'Afourer' mandarin with 50 Susbin-TMA traps per ha, in both grid and perimeter layouts. Five thousand sterile males were released in the center of each plot, and catches were evaluated. The mean recapture of sterile males was 14,9 and 3.3 in the grid and a perimeter design respectively. C. capitata population were controlled, and SIT could be applied in combination with mass trapping in a perimeter design without requiring a substantial increase in the sterile male dose released. © 2022 Informa UK Limited, trading as Taylor & Francis Group