Acidic and alkaline pectinases have proved efficient for the scouring of cotton. Peracetic acid can be used as an alternative for the bleaching of cotton. As a result of similar conditions of activity, we decided to try to scour and bleach a cotton fabric with both agents simultaneously in a single bath. Prior to performing these experiments, using the viscometric method we proved that pectinases retained their activity in the presence of peracetic acid. We tried to improve the efficiency of the single-bath treatment with the addition of a chelator. Tetrasodium pyrophosphate, which does not deactivate pectinases, has proved an efficient chelator. The analyses of a cotton fabric treated in a single bath with acidic and alkaline pectinases confirmed the efficiency of such treatment. A sufficient quantity of wax and pectin was removed and, because of that, the absorbance of the treated fabric was improved. The damage to the cotton fibres was negligible and the degree of whiteness obtained was uniform and adequate for further dyeing.