A method for simultaneous covalent immobilization of glucose oxidase and peroxidase with previously oxidized carbohydrate residues to urea derivative of regenerated acetylcellulose granules is described. The effect of immobilization on the catalytic properties of the separately immobilized enzymes are studied. The immobilized enzymes manifested no change in their pH and temperature optima and slight increase of K-m compared to data for the soluble enzymes. A column packed with simultaneously immobilized enzymes is used for manual glucose determination in blood sera. The results are in high correlation with those obtained by the Beekman Glucose Analyzer method (r = 0.976). The method is economic (the enzyme-carrier conjugate may be used more than 300 times), easy to perform, and less time consuming than the manual methods utilizing soluble enzymes. The established manual method can be proposed for emergency clinical analysis and smaller clinical laboratories.