The mechanical and fracture performance of a modified epoxy resin cured with an amine hardener containing block copolymer and/or core-shell rubber nanoparticles (CSR) were investigated in the current work. The effect of adding a resin, i.e. fluoren di epoxy resin, to the bisphenol- F based epoxy resin was also investigated. The fracture energy of the neat bis-F (i.e. unmodified) epoxy polymer increased slightly from 0.10 kJ/m2 to 0.14 kJ/m2 due to the addition of 7 wt% of the fluoren di epoxy to the bis-F epoxy. The fracture energy of the modified epoxy polymer increased to 0.530 kJ/m2 and 0.640 kJ/m2 when 12 wt% of the CSR nanoparticles and 8 wt% of diblock copolymer were added to the modified epoxy separately respectively. Furthermore, the addition of D51N block copolymers and MX170 coreshell rubber particles performed to give hybrid epoxy polymer nanocomposites, i.e. which contained an equal amount of BCP’s and CSR nanoparticles. No significant improvements in toughness were found for the hybrid epoxy polymer nanocomposites. The measured toughness of the hybrid materials can be related to the degree of dispersion of both nanoparticle phases in the epoxy polymer matrix. The toughening mechanisms were identified using SEM/EDAX fractography studies.