A pressure energized seal to seal an annulus between two concentric cylindrical members, particularly well suited to be used as an annular casing seal in an oil and gas well. A circular sealing ring has both its upper and lower surfaces channeled to leave two upper sealing lips and two lower sealing lips which effect the seal by being forced against the sealing surfaces of the cylindrical members. Two circular setting rings can be used to spread the sealing lips into sealing engagement with the sealing surfaces of the cylindrical members. The setting rings would be partially disposed within the channels of the sealing ring and adapted to spread the sealing lips when the setting rings are moved toward the sealing ring.