The aim of this study was to determine the presence of ectoparasites in the gills of 73 adult tilapia (Oreochromis niloticus) from seven ponds located in the Bello Horizonte Sector, Banda de Shilcayo district, San Martín, Peru. Sampling was carried out between January and February 2021. Measurements of size, temperature and pH of the ponds were recorded and the measurements of the ponds and fish density were obtained from fish farms records. The fish were taken to the laboratory for the dissection of the gills and the collection and fixation of the ectoparasites. Results showed that 35.6% (26/73) of fish were infested with one or more ectoparasites. The presence of monogeneans of the genus Chclidogyrus sp, family Dactylogyridae (28.8%) and the protozoan Trichodina sp (11.0%) (8/73) was determined.