In this research work, we report an efficient and easy method for preparation of 2-arylbenzimidazoles from o-phenylenediamines and phenoxyacetic acids under microwave condition using a Wells-Dawson heteropolyacid (H6P2W18O62 center dot 24H(2)O) as catalyst. The heterogeneous reaction conditions provided a very simple, environmentally friendly, clean, economical and selective protocol, for the preparation of benzimidazole derivatives. The catalyst is easily recycled and reused without loss of the catalytic activity.