Concrete is well known for its durability. However, it is exposed to aggressive agents, such as water and chlorides, leading to its degradation. The DC-electrical resistivity method is a technique devoted to non-destructive evaluation (NDE). However, when applying this measurement technique to reinforced concrete structures, the measurements may be highly influenced by the presence of reinforcement. To study the influence of reinforcements and estimate the impact of their effect on resistivity measurements on concrete, we model their contribution by finite element numerical analysis. Electrical measurements in reinforced and unreinforced concrete slabs were modelled and actual experimental measurements were used. This article presents the numerical study results that are compared to the experimental data for validation purposes. By validating the presented approach, it will be possible to fully account for the effect of the reinforcements, as an alternative to measurement strategies that aim at minimizing the disturbance due to reinforcements.