Methyl and phenyl oxazoline were polymerized using carboxylic acid chlorides as initiators. The first step of the reaction was shown to consist in a fast reaction of the carboxylic acid chloride with the oxazoline. Resulting product, which was isolated and identified, act as the proper initiator of the polymerization of the oxazoline, which proceeds via covalent or, when chloride counter ion is replaced with iodide or triflate, ionic active species. Apparent rate constants of the chain growth were determined. When methacryloyl chloride is used as initiator macromonomers are obtained, which were copolymerized with styrene. Macromolecular carboxylic acid chlorides initiate the polymerization of oxazolines, yielding graft polymers.