The objective of this study is to optimize experimental conditions of the phenol adsorption process onto granular activated carbon by using an experimental design methodology. The process is studied in a fixed-bed reactor. A rotatable and orthogonal central composite design at live levels allowed us to acquire a second-order model with the terms of interaction between the four influential factors chosen. The optimal values of flow rate solution, carbon bed height, temperature, and initial phenol concentration of the solution are equal to 1.67 mL.s(-1), 14.72 cm, 30 degrees C, and 94.35 mg.L(-1) respectively. An optimal adsorption yield (99.33 %) is acquired after only 1 h of experimentation.