The effect of axial loading resulting from torque on the fatigue life of bolts has been investigated. It was found that the fatigue limit of bolts increased by an amount proportional to the increase in torque. There was a linear relationship between torque and fatigue limit. Using the Shigley method, the prediction of fatigue limit from calculated stress concentration factors was also examined. A good correlation was found between the experimental and predicted fatigue limit. The Shigley method was appropriate for the prediction of fatigue life of bolts.