Poly(hydroxy ether of bisphenol-A) (phenoxy resin) and diglycidyl ether of bisphenol-A type epoxy resin (DGEBA) are found to be excellent compatibilizers for polyamide 6 (nylon 6)/methyl methacrylate-styrene-butadiene (MBS) graft polymer blends. When the blends are modified by phenoxy of DGEBA, phase dispersion, mechanical properties and rheological properties are significantly improved. The compatibility between phenoxy and MBS is based on thermodynamic miscibility between phenoxy and poly(methyl methacrylate) in MBS. The compatibility between nylon 6 and phenoxy seems to originate from the reactivity between functional groups of the two polymers. The compatibility between DGEBA and MBS is also based on thermodynamic miscibility between the chain component of the epoxy and poly(methyl methacrylate) in MBS. The compatibility between nylon 6 and the epoxy resin originates from reactivity between the functional groups of the two polymers. The role of phenoxy or DGEBA as compatibilizers in nylon 6/MBS blends is demonstrated and the two compatibilizers are compared.