The effects of counter-anions on the microphase-separated structure and the properties of elastomeric ionene polymers (PTV) containing poly(tetrahydrofuran) (poly(THF)) soft-segment blocks and viologen hard ionic segments were investigated by thermal and mechanical analyses and by a small-angle X-ray scattering (SAXS) technique. Three sorts of PTVs having Cl-, Br-, or I- halide ions as counter-anions for the viologen groups were synthesized. All PTVs showed good elastomeric properties, i.e. low tensile modulus, high tensile strength and high elongation at break. The PTV with Cl- anions showed a higher capability of crystallization of the poly(THF) block chains than those with Br- or I- anions, in the cooling process prior to successive thermal and dynamic viscoelastic measurements, and exhibited a higher glass transition temperature of the amorphous poly(THF) chains in the heating process of these measurements. In the SAXS experiments, all PTVs exhibited multiple scattering peaks, indicating that microphase separation between the poly(THF) block chains and the viologen units was highly ordered. On the basis of these results, we considered a lamellar-type microphase-separated structure for PTVs with halide counter-anions.