The present invention relates to an improved process for the preparation of Letrozole (I) and its synthetic intermediate 4 [(1 (1 2 4 triazolyl)methyl]benzonitrile (III). In particular it relates to a process to prepare Letrozole and its intermediate (III) substantially free from regioisomeric impurities. The present invention further relates to acid addition salts of 4 [(1 (1 2 4 triazolyl)methyl]benzonitrile (III) such as the oxalate salt and also to Letrozole (I) the intermediate (III) and salts thereof preparable by the processes of the present invention.
