Maleated ethylene-propylene-diene rubber (EPDM-g-MA) toughened polyamide 6 (PA6)/organoclay (OMMT) nanocomposites were prepared by melt blending. The role of OMMT in the morphology of the ternary composites and the relationship between the morphology and mechanical properties were investigated by varying the blending sequence. The PA6/EPDM-g-MA/OMMT (80/20/4) composites prepared by four different blending sequences presented distinct morphology and mechanical properties. The addition of OMMT could obviously decrease viscosity of the matrix and weaken the interfacial interactions between PA6 and EPDM-g-MA when blending EPDM-g-MA with a premixed PA6/OMMT nacocomposite, resulting in the increase of rubber particle size. The final mechanical properties are not only determined by the location of OMMT, but also by the interfacial adhesion between PA6 and EPDM-g-MA. Having maximum percentage of OMMT platelets in the PA6 matrix and keeping good interfacial adhesion between PA6 and EPDM-g-MA are beneficial to impact strength. POLYM. ENG. SCI., 49:209-216, 2009. (C) 2008 Society of Plastics Engineers