Structural health monitoring has crucial importance to protect the lives and to organize the management of concrete structures. Development of self-sensing smart materials will enable cost effective, robust and reliable solutions for structural health monitoring of concrete. In this study, twenty one cement mortars without and with carbon fibers reinforcement were produced and their compressive strength was tested. Simultaneously, the correlations between strain and electrical resistance change of all mortars were determined. Performance parameters of a strain sensor, which are gauge factor, linearity and strain limit, were evaluated for these cement mortars. The results showed that the cement mortars were much more sensitive to strain than commercial metal strain gauges, while they had a little error of strain estimation. The strain limits were found to be high enough for the mortars without and with carbon fibers reinforcement to be used as strain sensors for concrete structures. This study is a contribution to develop smart materials as sensors for the concrete constructions.