This invention relates to a process for preparing eprosartan by reacting 4-[(2-n-butyl-5-formyl-1H-imidazol-1-yl)methyl]benzoic acid or the bisulfite addition compound of 4-[(2-n-butyl-5-formyl-1H-imidazol-1-yl)methyl]benzoic acid with (2-thienylmethyl)propanedioic acid, mono-ethyl ester.