The present investigation was carried out in the Cañoncillo lagoon located in the district of San Pedro de Lloc, province of Pacasmayo, department of La Libertad. The objective of the research was to evaluate the eutrophication level of the Cañoncillo lagoon. To achieve this objective, five sampling points were identified along the water body, where in situ parameters such as pH, temperature, dissolved oxygen, electrical conductivity and water transparency were measured. In addition, two samples were collected from each point at different depths (1 m and 3 m) using a hydrographic bottle. Nitrates and phosphates were analyzed from each sample by the colorimetric method and chlorophyll-a by the trichromatic method. Two indices were then applied to determine the level of eutrophication of the lagoon: the Nutrient Eutrophication Index (EI) of Karydis et al. and the Trophic State Index (TSI...