The hydroxyethyl ester of naproxen (II) was synthesized by treatment of the sodium salt of naproxen (I) with 2-bromoethanol. Condensation of (II) with (4-methyl-1-piperazinyl)acetic acid (III) in the presence of dicyclohexylcarbodiimide and 4-(dimethylamino)pyridine yielded the title compound.