AbstractTransversely bianisotropic uniaxial medium can be constructed by mixing metal helices into anisotropic host medium in such a way that the axes of the helices are perpendicular to a fixed direction in space but randomly oriented in the transverse plane. In general, the host medium can be either reciprocal or nonreciprocal. Eigenwaves, expressions for the plane‐wave fields, and polarization behavior are derived for the plane wave propagating perpendicular to the symmetry axis. The polarization properties of chiral and reciprocal transversely bianisotropic uniaxial medium are studied in order to find a suitable parameter combination for a polarization transformer. Several numerical examples are given to illustrate the propagation properties of the transversely bianisotropic uniaxial medium.