The present invention provides a process for the preparation of clopidogrel and its pharmaceutically acceptable salts thereof comprises the resolving racemic methyl alpha-5-(4,5,6,7-tetrahydro[3,2-c]thienopyridyl)(2-chlorophenyl)-acetate by the salt formation of methyl alpha-5-(4,5,6,7-tetrahydro[3,2-c]thienopyridyl)(2-chlorophenyl)-acetate with excess levorotatory camphor-10-sulfonic acid to get a maximum yield of camphor sulphonate salt of methyl S-(+)-alpha-5-(4,5,6,7-tetrahydro[3,2-c]thienopyridyl) (2-chlorophenyl)-acetate and transforming the camphor sulphonate salt to clopidogrel or its pharmaceutically acceptable salts thereof.