Semi continuous emulsion polymerization studies were carried out in one-litre glass reactor to study the effect of various methods of initiator addition and its effective concentrations. Thirty six runs were carried out to study the effect of various modes of addition of initiator at fixed time intervals of 2, 3 and 4 h with ratio of monomers, speed of agitation and reaction temperature being constant. Initiator was added in two ways, i.e. (a) pinch addition (addition at specific time interval), (b) continuous addition: (i) addition of initiator along with monomer emulsion mixture, (ii) separate continuous addition. Objective was to obtain high solid content emulsion with linear low viscosity polymer. Linear and less viscous emulsions were obtained when initiator was added separately.