Radical emulsion polymerizations of vinylcyclopropanes, 1,1-bis(ethoxycarbonyl)-2-vinylcyclopropane (ECVCP) and 1,1-dichloro-2-vinylcyclopropane (CVCP) were examined. ECVCP underwent soap-free and soap-in emulsion polymerizations satisfactorily to afford the ring-opened polymer in good yields. Polymer emulsions were obtained in a spherical shape with single particle size distribution. Meanwhile, emulsion polymerization of CVCP proceeded in only a low conversion.