An all plastic compression spring assembly includes a slotted tubular spring element formed from a tensile polymer material and first and second loading cones received at opposing first and second ends of the slotted tubular spring element. The loading cones are axially compressible toward each other within the slotted tubular spring element whereby the slotted tubular spring element radially expands in tension to create an opposing radial contraction force, and in turn, an axial extension spring force. When released, the spring element elastically returns to its normal at rest shape, returning the cones to their normal at rest positions.