AbstractMechanical and electrical properties of ethylene propylene rubber (EPR) pieces were studied in comparison with polyethylene (PE) in the cryogenic temperature region to examine the possibility of its application to the solid electrical insulation material of superconducting cables. Mechanical properties of EPR are preferable to those of PE because of its low shrinkage. The electric strength and dielectric loss tangent of EPR are comparable with those of PE at liquid helium temperature. The use of EPR as an solid electrical insulation of superconducting cable is discussed based on the results obtained.