Predictive mathematical models were developed for removing Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS) and optimizing the main operating parameters of the Fenton process, applied to effluents from a fish canning industry. The maximum removals obtained for COD and TSS were 89.2 % and 76.1 %, respectively. The optimum doses for COD removal were: 200 mg/L FeSO4 7H2O and 1,000 mg/L H2O2 at pH 2.5. While for TSS removal the optimum parameters were 1 200 mg/L H2O2, 300 mg/L FeSO4 7H2O, and pH 3. The adjusted R2 values of the COD and TSS removal models were 70.64 % and 98.01 %, respectively, indicating that the models obtained are acceptable in the prediction of both parameters.