Abstract: Fluid polymer polyol dispersions which impart improved fire resistance to polyurethane foam. The fluid polymer polyol dispersions are prepared by grafting one or more monomers onto a polyol backbone with the difference that the grafting takes place in the presence of a flame retardant. During the grafting process the flame retardant is incorporated into the fluid polymer polyol dispersion. When such fluid polymer polyol dispersions are used, the fire resistance of the final polyurethane foam is improved relative to cases where a conventional fluid polymer polyol dispersion and a flame retardant are added separately to the polyurethane foam formulation.