Summary Drillstrings made before 1982 were not designed to meet the rigorous demands of today's drilling. Deeper wells and higher-angle holes are requiring higher pump pressure, and more tensile and torque capacity. Back-reaming, with the use of a power swivel, is agitating these conditions even further. Recent work has been done to improve the fatigue life of drillpipe by making drillpipe with longer internal-taper upsets and stress-relief grooves. Even though improvements have been made, slip damage still takes its toll on drillpipe. This paper addresses the failures caused by slip damage and offers a solution for solving this problem. Finite element work and fatigue testing has been done to prove the effectiveness of this new drillpipe design.