Epoxy nanocomposites are widely used materials in engineering applications from automobiles to aircraft. However, their low fracture toughness significantly hinders their usefulness due to the possible catastrophic failure caused by the small cracks or defects. Herein, we demonstrate that inverse nacre-like epoxy-graphene layered nanocomposites with high toughness can be fabricated using the freeze-casting technique, which has promise to solve the problem of poor crack resistance for traditional epoxy-graphene nanocomposites. In addition, the continuous graphene-based scaffold in the epoxy matrix endows this epoxy-graphene nanocomposite with electrical conductivity and confers on it a self-monitoring function. The propagating cracks can be detected by the variable electrical resistance, thus making future nanocomposites safe and more secure.