The toughness of three different elastomer-toughened nylon 1010 blends was investigated via standard notched Izod impact test and single edge notched three-point bending test. The toughness of nylon 1010 blends varies much with different elastomer types and components. All three kinds of nylon/elastomer/maleated-elastomer blends showed high impact strength (over 50 kJ m(-2)) as long as at appropriate blending ratios. With increasing maleated elastomer content, brittle-ductile transition was observed for all three kinds of elastomer-toughened nylon 1010 blends. The number average dispersed particle size (d(n)) of ethylene-1-octene copolymers or ethylene-vinyl acetate copolymers toughened nylon 1010 blends significantly decreased from over 1 to 0.1 mu m with increasing corresponding maleated elastomer content. Investigation on the fracture toughness showed the dissipative energy density gradually increased with decreasing d(n), while the limited specific fracture energy increased with increasing d(n) when d(n) was below 1 mu m and then sharply decreased with further increasing d(n). The energy consumed in the outer plastic zone was the main part of the whole energy dissipated during the fracture process. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3340-3346, 2011