The formation of behenic acid monolayers at the air/water interface has been studied in the presence of glucose oxidase. When the enzyme is present in the subphase, spreading of behenic acid at the air/water interface leads to the formation of a mixed film of glucose oxidase and behenic acid, The pressure-area isotherms performed with various concentrations of the enzyme in the subphase showed the incorporation of the enzyme in the monolayer, The dynamics of the mixed films was studied by following the evolution of the film area at a constant pressure and the evolution of the pressure at a constant area, Glucose oxidase dramatically stabilizes the behenic acid film, A limit pressure of incorporation of glucose oxidase in the behenic acid film at the air/water interface was observed at 28 mN/m.