A new approach to the electromagnetic theory of a moving isotropic chiral medium is presented. The relation between the index of refraction in the two frames (co-moving and laboratory) is derived without using any constitutive relation. A generalized Bohren’s decomposition is stated: a moving chiral media is given by the
superposition of two isotropic moving media. This new approach is simpler than the traditional one based on the constitutive relations as seen from the lab frame. The two approaches are shown to be equivalent.