3D-chiral metamaterials are constructed from chiral materials or resonators in which the effective chirality parameter κ κ is non-zero. Wave propagation properties in such chiral metamaterials demonstrate that negative refraction can be realized in metamaterials with a strong chirality and positive ε ε r and μ μ r . This is because the refractive index n has distinct values for left and right circularly polarized waves, given by