Calcium carbonate powder comprising uniform nanoparticles of novel morphology was synthesized under extensively optimized trial parameters. The as-prepared ultrafine rod shape CaCO3 particles after characterizations were used as an antiwear/antifriction additive in commercial lithium grease (CLG) of different specifications. The effect of the added particles on the antifriction and antiwear properties of the blended commercial greases was explored by using a ball-on-disk tribometer. The observed data were compared with the additized grease having commercially available CaCO3 powder. Results exposed that uniformity in particle size and shape is a key factor for the improvement of tribological properties and reproducibility of the experimental results. Therefore, the as-prepared monodispersed rod shapes CaCO3 particles as additives considerably improved the tribological properties of the CLG as compared with the irregular particles of the commercial calcium carbonate. These blends showed the best results at the optimum amount of 3 wt% of the added CaCO3 particles. Among the three selected greases, the additized Momin grease exhibited best antiwear/antifriction performance as compared with the additized Awami and Sinopec greases.