The Rolling Contact Fatigue (RCF) behaviour of through-hardened AISI 4140 samples under formulated lubricant with nano-graphene additives were investigated. Results showed that the reference oil added with 1% (wt.) of nano-graphene particles has significantly improved life by 6 folds. The increased RCF performance is attributed to the efficient action of graphene nano particle which improves the antiwear and pitting resistance of contact pairs. Moreover, spectroscopy and microscopy analyses indicated that graphene particles are adsorbed on the contact surface and delay the surface pit formation. Adding nano-graphene particles in the reference lubricant is an effective way to improve the RCF life under thin oil having low lubricant viscosity and also for the samples having lesser surface hardness such as through- hardened compared to induction-hardened samples.