Alkylation of aniline with n-propanol and isopropanol over ZSM-5 and Y-zeolites in vapour phase have been studied under atmospheric pressure to understand the difference in the reaction mechanisms. Alkylation of aniline with n-propanol gives N-n-propylaniline, o-n-propylaniline and p-n-propylaniline via the SN2 mechanistic pathway as well as the products N-isopropylaniline, o-isopropylaniline and p-isopropylaniline via an SN1 mechanism. Alkylation of aniline with isopropanol produces N-isopropylaniline, o-isopropylaniline and p-isopropylaniline; here both SN1 and SN2 mechanisms are operative.