Abstract: The present invention refers to the procedure for the preparation of aqueous concentrated solutions of low viscosity carboxymethylcellulose by enzymatic depolymerisation of medium viscosity carboxymethylcellulose in the form of dispersed powder in a hydro-alcoholic heterogeneous medium, and to such aqueous concentrated solutions which have Brookfield viscosity, at 20° C. and 20 rpm, comprised between 2000 and 5000 mPa*s. Preferred alcohol-water biphasic systems have from 40% to 50% of alcohol (e.g., ethanol or isopropanol). The aqueous solutions of carboxymethylcellulose produced are stable over time, and their viscosity varies no more than 10% in 3 months.