This research work is focused on the evaluation of the effect of annealing on the microstructure and mechanical properties of rolled steel products. The material used for this research work includes mild steel round bar of dimension 30mm diameter and length 175mm. The mild steel round bar was divided into Sample A, Sample B, Sample C and Sample D respectively. Each of the samples was properly machined to the required shape using a lathe machine. Four samples of 55mm in length were used to produce round steel bar which was used for investigation of impact tests. The samples were observed for metallographic structural inspection. Subsequently, tensile strength test and impact test of the material were carried out. The results obtained reveal that annealing heat treatment influences the mechanical properties of the rolled steel. An improvement in ductility of materials was recorded. Above and beyond, the microstructure analysis results show that between the temperatures of 6500C – 7500C, there was no serious transformation despite the precipitation of the carbon. However, between 7500C – 8500C, serious transformation was recorded.