We investigated the rheological behavior and film casting processability of PMMA blended with core-shell rubber (CSRP) which has been used for various applications because of its excellent transparency and mechanical properties. Various types of core-shell rubbers (CSRs) were prepared by emulsion polymerization, e.g., high or low dispersity of CSR into PMMA by changing the composition of graft polymer on the core rubber. We carried out linear viscoelastic properties of various types of CSRP and evaluated their film processability (die line and draw resonance). The storage modulus G’ and the loss shear modulus G” of CSRP were influenced by contents of the rubber, degree of crosslinking of the rubber and polymer content of the shell grafted on the rubber (core). At low frequency G’ and G” of CSRP showed the weak frequency dependence, while PMMA indicated the terminal relaxation. And this tendency was more conspicuous than that of CSR which has miscible graft polymer with matrix in comparison with CSR with low affinity to PMMA. The relaxation modulus G(t) was also increased by the contents and affinity of the rubber. An introduction of various CSRs influenced the film casting behavior of CSRP, especially in occurrence of die line. CSR which has better affinity to PMMA gave rise to a lot of die lines compared with CSR with immiscible grafted polymer with the matrix. Moreover, draw resonance was observed only in CSRP blended with CSR, on which the immiscible polymer was grafted. We will discuss these film casting behaviors in terms of the miscibility of CSR and the relaxation time of CSRP. Key words:PMMA, core-shell rubber, viscoelasticity, affinity, graft polymer