AbstractPolyalphaolefin (PAO) fluids have become widely accepted as high‐performance lubricants and functional fluids due to certain inherent, and highly desirable, characteristics. One of these characteristics is their low toxicity, which, combined with excellent viscometrics and lubricity, have made low‐viscosity PAO fluids an important component in lubricant formulations.Typical data found in product specifications for lubricants are the kinematic viscosity and the viscosity index. These values do not give enough information with which to choose the optimum lubricant for a lubricated contact. In mechanical systems, rolling, sliding, and rolling/sliding contacts occur, and lubricants have to work optimally under these operating conditions.In this study the rolling‐contact fatigue lives (L50and L10) of PAOs of different viscosities were experimentally determined. The tests were carried out using a four‐ball machine. Wear tests were also carried out using another four‐ball tester in order to measure the wear‐scar diameter and the flash temperature parameter. The lubricants were characterised by infrared spectroscopy, and the pitting of the balls was observed using scanning electron