A series of 5-(alkyl and aryl)carboxamido benzimidazole derivatives had been designed, synthesized and evaluated for in vitro angiotensin II - AT(1) receptor antagonism and in vivo antihypertensive activities. The pharmacological activities were inversely related to the size of alkyl and aryl substituents. It can be suggested that compounds with lower alkyl groups at 5-position of benzimidazole nucleus demonstrated potent antihypertensive activity. (C) 2007 Elsevier Masson SAS. All rights reserved.