Disclosed is a method for producing a rubber modified thermoplastic resin excellent in surface appearance and various properties and high in commercial values which comprises removing an aqueous phase from a two-phase mixture comprises a graft rubber polymer latex (1) obtained by graft polymerization of vinyl monomer on a rubber latex, a thermoplastic resin (2) and an organic agent in an amount of 0.2 to 6 times the weight of all the polymers (3) which is capable of dissolving said thermoplastic resin (2) and has a solubility in water of 5 to 50% by weight at 25.degree. C. and then removing said organic agent and remaining water from the remaining organic phase by a thermal means.