Pure rolling contact fatigue tests were carried out on a two-disc machine. The longitudinal cracks were initiated on the specimen surface with pure rolling and rough driving disc conditions. Cracks were easily formed from the initial longitudinal finishing grooves on the surface. The crack distribution in the wear track depended on the elastohydrodynamic lubrication (EHL) condition. If the film thickness parameter A was less than 0.1, most of the cracks were found at the center part of the wear track. With increasing A, cracks were located towards the two sides of the wear track. When A was greater than 0.5, the initiation of surface cracks was difficult except in the region near the surface defects. Three mechanisms of crack initiation under pure rolling conditions are postulated based on the micro-macro contact mechanics and micro-EHL theory.Presented at the 48th Annual Meeting in Calgary, Alberta, Canada May 17–20, 1993