Abstract: An improved sliding pipe joint seal for use in sealing an annular space created between a sealing surface of a spigot at an end of a length of pipe and a sealing surface of a bell shaped end of another length of pipe when the two pipes are connected end-to-end. The pipe joint seal includes an annular body having an inner gripping surface and an outer tab. The gripping surface is adapted to engage the sealing surface of the spigot to retain the seal thereon. The body has a normally closed annular chamber storing a lubricant, such as a grease. An annular slit in the body extends into the chamber forming a flap intermediate the slit and tab. The slit is spread apart when the bell shaped end engages the seal as the pipes are joined, thereby releasing the grease against the sealing surface of the bell shaped end as the seal slides over the remainder of the sealing surface of the bell shaped end.