Disclosed is a process for producing a polymer polyol, comprising: (a) reacting a first mixture comprising an initiator, a polyol, a diluent, a stabilizer, a styrene-based monomer and a nitrile-based monomer; and (b) continuously adding, to the first mixture, a second mixture comprising an initiator, a polyol, a stabilizer, a styrene-based monomer and a nitrile-based monomer to react, wherein the first mixture and second mixture comprise the stabilizer in a weight ratio of 1:1 to 3, respectively, and a polymer polyol produced according to the process.