Two commercially available medium carbon and low carbon microalloyed steel were evaluated in this study. The steels were cold strained in tension 5 % and were aged at 100-450 degrees C for 1 hour. Strained and aged specimens were then retested to fracture and mechanical properties of steels were measured. Changes in mechanical properties such as ultimate tensile strength and yield strength were observed at ageing temperatures. This ageing is ass degrees Ciated with interaction between interstitial solutes and disl degrees Cations which are preferential sites for solute atom diffusion. Indications are that the medium carbon microalloyed forging steel is more susceptible to strain ageing than the low carbon microalloyed steel as evidenced an increase in yield strength and tensile strength.