It is provided a method for obtaining Irbesartan polymorph A, with few synthesis steps, by coupling the intermediate of formula (II) with the compound of formula (III), neutralising one of its alkaline salts in an aqueous medium and recrystallising the crude product obtained. The utilisation of said method obviates protection and deprotection of the tetrazole ring and is therefore of considerable interest for obtaining Irbesartan on a large industrial scale. The invention also refers to the synthesis intermediate of formula (II). ##STR00001##