N-Alkylmethacrylaldimines were prepared directly from methacrolein and primary amines. Polymerization of some kinds of α,β-unsaturated aldimines were examined using various kinds of initiators. Methacryl- and acrylaldi-mines were polymerized by anionic catalysts. Polymerization of these imines proceeded exclusively through vinyl-opening. From the results of homo- and copolymerizations of cyclohexylmethacrylaldimine (HMI) and/or other conjugated vinyl monomers, anionic polymerizabilities of these monomers was found to decrease in the order: