The problem of fretting fatigue is becoming more acute as increasing demands are placed on materials. Consequently, a program has been initiated to investigate the fundamental mechanisms and conditions that govern fretting fatigue. One of the initial steps taken has been the development of an experimental apparatus and test technique that allows the fretting and fatigue process to occur simultaneously. In addition, loads are monitored continually on the apparatus in the hope that quantitative relationships may eventually be developed relating fretting damage to life. The apparatus is discussed in detail and typical results presented in the paper.