The present paper describes a new type of polymerization of 2-vinyl-2-oxazoline and 2-vinyl-5,6-dihydro-4H-1,3-oxazine and their salts. When these two imino ether monomers are allowed to react with Meerwein reagents or super acid esters,N-alkylation takes place first, followed by polymerization through the opening of vinyl groups to give poly [(2-oxazolinium-2-yl)ethylene] and poly [(5,6-dihydro-4H-1,3-oxazinium-2-yl)ethylene], respectively. With the corresponding 2-isopropenyl homologs, 2-isopropenyl-2-oxazoline and 2-isopropenyl-5,6-dihydro-4H-1,3-oxazine, stableN-alkylated salts are obtained, which were subjected to radical and base-catalyzed polymerizations. From the above results the reactivities of the salts are considered in terms of their ring size and the substituents on the olefinic functions.