Abstract: The present invention relates to an improved process for the preparation of anastrozole having enhanced purity from crude anastrozole having isomeric impurity content up to less than 1%. The invention also relates to a process comprising steps of converting (3-cyanomethyl-5-methylphenyl) acetonitrile to 2-[(3-cyanodimethylmethyl)-5-methyl phenyl]- meiliyl propiononitrile (II) by C-alkylation, which is further converted into 2-[3-halomethyl-5-cyanodimethyl methyl)phenyl] methyl propiononitrile (ill) by radical bromination and further to crude anastrozole by reacting (III) with sodium salt of 1,2,4-triazole, purification of the crude anastrozole by preparing its acid addition salt, generating required final anaslrozole from the acid addition salt.