A process of preparing imatinib, either as the free base or as an acid addition salt, which process comprises reacting N-(2-methyl-5-aminophenyl-4-(3-pyridyl)-2-pyrimidine amine of formula (II) with a 4-(4-methyl-piperazino methyl)benzoyl halide of formula (III) in the presence of an inert organic solvent, so as to yield a hydrohalide salt of imatinib formula (I) where n represents 1, 2 or 3 and Hal represents bromo, chloro, fluoro or iodo, either in anhydrous or hydrated form, which can as desired optionally be further converted either to the free base or a further acid addition salt. The present invention is also concerned with imatinib prepared according to the above process. ##STR00001##