This paper presents a non-destructive capacitance-based technique for rebars detection in reinforced concrete structure. The proposed technique depends on capacitance variation between the two electrodes of a co-planar capacitive sensor while scanning across different concrete sections with and without reinforcement bars. A mathematical model is used to provide meaningful interpretation for the effect of different sensor and concrete parameters on the measured capacitance. The finite element model is built and accompanied by a dedicated experimental setup to confirm theoretical estimations. Simulation and experimental results confirmed a detectable capacitance variation while scanning across the reinforced concrete slab in experimental setup for rebars detection.