A process for preparing carboxymethyl ethyl cellulose (CMEC) suitable for enteric coating which comprises (1) adding an alkali metal hydroxide and water to a substantially water-immiscible organic solvent dispersion of carboxymethyl cellulose (CMC) and reacting CMC with an ethyl halide in the presence of a phase transfer catalyst, (2) dissolving the produced CMEC in an aqueous solution of a basic compound selected from the group consisting of ammonia, a water-soluble amine and an alkali metal hydroxide and subjecting the resulting solution to depolymerization in the presence of a peroxide, (3) neutralizing the resulting basic reaction mixture with an acidic substance in the presence of a lower alkyl alcohol or acetone to form a hydrogel of the depolymerized CMEC, subjecting the hydrogel to dehydration with agitation, isolating the depolymerized CMEC and washing with water, and (4) drying the wet depolymerized CMEC without pulverization or after pulverizing in the wet state to particles having an average particle size of at most 100 .mu.m. The product has an excellent quality, and is easily soluble in organic solvents and easily dispersible in water, and provides a coating film having excellent strength, resistance to gastric juice and solubility in intestinal juice. Also, the solubility in organic solvents and dispersibility in water of the product can be controlled by selecting the basic compound used in the depolymerization.