The effect of viscosity modifiers on the flow properties of prevulcanized NR latex (PVL) was studied at different shear rates and temperatures. PVL exhibited pseudoplastic flow pattern. The pseudoplasticity decreased on increasing temperature. The viscosity of PVL can be increased by the addition of viscosity modifiers such as casein, polyvinyl alcohol (PVA) and sodium carboxymethyl cellulose (NaCMC), the predominant effect being obtained by the addition of NaCMC.