In this paper, the response surface methodology (RSM) approach using central composite design (CCD) was applied to develop mathematical model and to optimize process parameters for COD and TSS removal from tannery wastewater by electrocoagulation and electro-Fenton processes using iron electrodes. Analysis of variance (ANOVA) was used to analyze the data and to obtain the interaction between the process variables and the responses. ANOVA showed the relative significance of process parameters in the removal process. The second-order regression model was developed to predict the removal efficiency using Statgraphics Centurion XVI.I software program. The optimal conditions were determined as reaction time 5.0min, pH 3.31, current density 53.72mA/cm(2), and H2O2 dose 0.14g/L for electro-Fenton process, and reaction time 40.4min, pH 7.0, and current density 50.9mA/cm(2) for electrocoagulation process. At optimum conditions 54.8 and 87.3% COD removal efficiencies, 86 and 88% TSS removal efficiencies were achieved in electrocoagulation and electro-Fenton processes, respectively. The operating costs for elecrocoagulation and electro-Fenton processes at optimized conditions were calculated to be 6.4 and 6.8Euro/m(3). Electro-Fenton process was found to be more effective for tannery wastewater treatment.