The maleated poly(ethylene I-octene) (POE-g-MAH)-toughened and glass fiber (GF)-reinforced nylon 1010 was prepared by melting extrusion. A good trade-off between stiffness and toughness was obtained by the combination of POE-g-MAH and GF. The essential work of fracture (EWF) model was used to characterize the fracture behavior of nylon/POE-g-MAH/GF composites. With increasing GF content, the energy Consumed in enter plastic zone gradually decreased, and the work consumed in inner fracture process zone reached the maximum Value at the GF, content of 10 wt %. Morphology investigations showed that POE-g-MAH was uniformly dispersed in nylon/POE-g-MAH (80/20) blend, and the nylon around POE-g-MAH Particles suffered a great plastic deformation in the impact test. For nylon/POE-g-MAH/GF composites, large plastic deformation occurred hi the matrix around GF rather than around rubber particles. Dynamic mechanical analysis showed that GF significantly increased the storage and loss moduli and decreased value of tan delta, but had little effect on its position. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 181-189, 2009