This invention provides a polymer polyol composition (I) comprising a polyol (A) and polymer particles (B) dispersed in (A), the polymer particles (B) being formed by polymerizing an ethylenically unsaturated compound (b) in a polyol, wherein the content of (B) in (I) is from 35 to 75 mass %, based on the mass of (I), and the amount of soluble polymers (P) dissolved in (A) is not more than 5 mass %, based on the mass of (A), and provides methods for producing the polymer polyol composition (I). Further, this invention provides a method for producing a foamed or non-foamed polyurethane resin, which method comprises reacting a polyol component with a polyisocyanate component in the presence or absence of a blowing agent, wherein the above polymer polyol composition is used at least as a portion of the polyol component. A polymer polyol having a low viscosity and excellent dispersion stability is provided even when having a high concentration of polymer particles, and is used advantageously to produce polyurethane resins having excellent 25% ILD (hardness) and compression set, or foams thereof, with good operation efficiency.