A process is disclosed for removing cellulose ether and other cellulose derivates from an aqueous solution/suspension. An effective and economical process that allows a considerably higher amount of cellulose derivate to be recovered from the wash water as in the state of the art, is characterized in that the flocculated cellulose derivates are removed in a first step from the solution heated over the flocculation point, the solution is subjected in a second step to a membrane filtration, after cooling down below the flocculation point, and the concentrate thus obtained is heated over the flocculation point and further concentrated.