Organotellurium-mediated living radical polymerization (TERP) of n-butyl acrylate (BA) in emulsifier-free emulsion polymerization system was carried out for the first time, using the in situ nucleation technique via self-assembly of the propagating amphiphilic polymer chains derived from water-soluble TERP agent, poly(methacrylic acid)-methyltellanyl, with water-soluble thermal initiator, 4,4'-azobis(4-cyanovaleric acid), as a radical source at 60 degrees C. The polymerization proceeded with high control/livingness to high conversion without coagulation, resulting in nanosized poly(BA) particles. The difference in the stirring rates of the polymerization system, where the whole monomer dispersed as droplets at a high rate or it existed as an upper layer on the aqueous medium at a low rate, had a great influence both on the rate of polymerization and on the degree of the control/livingness. On both of them, the polymerization with the high stirring rate gave more desirable results than those with the low rate.