In this study, biodegradable microparticles of silk sericin (SS)/silk fibroin (SF) blends with SS/SF blend ratios of 100/0, 75/25, 50/50, 25/75 and 0/100 (w/w) were fabricated by the water-in-oil emulsification-diffusion method. An aqueous SS/SF blend solution and ethyl acetate were used as the water and oil phases, respectively. The blend microparticles were nearly-spherical in shape with a rough surface. The internal morphology of microparticles was porous structure. The particle sizes slightly decreased as the SF blend ratio increased. FTIR analysis revealed that secondary structure of the SS changed from random coil to b-sheet form by blending with the SF. The dissolution of the blend microparticles strongly depended on the blend ratio.