Massive waste rubber products become very challenging because the disposal generates negative impacts on the ecological environments. The effect of conductive rubber crumbs replacing the fine aggregate on the physical, mechanical properties and electrical characteristics of cement composites were investigated in this study. The results show that the flowability of cement mortar increased when the rubber crumbs replacement rate lower than 10%, but decreased when the substitution rate higher than 10%. The compressive strengths of rubberized mortar were decreased with the increase of amount of rubber crumbs. However, as the amount of rubber crumbs increased, less reduction on compressive strength was observed for the cement mortar at water-to-binder (W/B) ratio of 0.42, because of the improved flowability. In terms of the electrical properties, both the near-surface resistivity and the volumetric resistivity of rubberized mortar were increased with the curing age because of the continuing cement hydration. The near-surface resistivity of cement mortar was limitedly affected by conductive rubber crumbs, while the volumetric resistivity did gradually decrease with the increase of rubber content. The developed cement mortar containing recycled conductive rubber crumbs can be used for manufacturing self-sensing concrete used for structural health monitoring.