The invention relates to an improved process for the preparation of Losartan. The process comprising reacting 2-n-butyl-4-chloro-5-formyl imidazole with 2-(4-bromomethyl) benzonitrile in the presence of a phase transfer catalyst and an alkali, and reducing the resulting cyano aldehyde to produce a cyano alcohol which is further reacted with sodium azide in N-methyl pyrrolidinone and a salt to produce Losartan.