Periodic operation of reaction temperature was examined as a means to control latex particle size distribution in the continuous emulsion polymerization of vinyl acetate. The experiment was conducted in a CSTR under conditions below the critical micelle concentration of the emulsifier. The monomer conversion attained in a time-independent steady-state operation showed a dramatic rise from 0 to over 60% at a critical reaction temperature of T-c = 53degreesC. The dynamic operation was performed by switching the reaction temperature between two values, one of which gives a very low monomer conversion and the other a high monomer conversion in the usual steady-state operation. The periodicswitching induced oscillations in monomer conversion, and the particle size distribution (PSD) varied synchronously with the switching operation.