The invention relates to a process for preparing hydroxyl- and carboxyl-containing polyesterimide resins, comprising as monomeric components: (A) imide-forming compounds having at least two primary amino groups and/or at least two isocyanate groups or imide-forming compounds having at least one primary amino group and/or at least one isocyanate group and at least one further functional group selected from hydroxyl, carboxyl and/or carboxylic anhydride, (B) polycarboxylic acids and/or their anhydrides and/or their esters and (C) polyols, characterized in that (I) component (A) is reacted with part of component (B) to form a polyimide, (II) the polyimide obtained in accordance with stage (I) is reacted with component (C) to form a polyesterimide, and finally (III) the polyesterimide obtained in accordance with stage (II) is reacted with the remaining part of component (B) to form the Also embraced by the invention is the use of the polyesterimides prepared by the process according to the invention as binders, and wire enamels comprising hydroxyl- and carboxyl-containing polyesterimides having an acid number >80 mg of KOH/g which can be prepared by the process according to the invention.