Concrete is the most important building material due to the availability of its constituent materials and its easy manufacturing; it is commonly reinforced with a steel bar to resist the tensile stresses. The present research discusses the effect of cement content on the bonding strength with the steel bar reinforcement as well as the concrete strength while fixing the fine/coarse aggregate proportion, the slump and the water/cement ratio. Two series have been produced by using different types of steel bars (smooth and deformed) with a different cement content of (250, 300, 350, 400 and 450 kg/m3). These two parameters were used to study the effect of the cement content and the mechanical interlocking on the bonding strength between concrete and steel bars. The results of this study showed that the compressive strength increases with the increasing of cement content up to 400 kg/m3, and then there is no significant improvement in compressive strength. However, the bonding strength with the steel bar increases even at 450 kg/m3. For any cement content, the deformed bars exhibited a better bonding strength of several times than the smooth bars.