Rapid developments in the aviation and power industries have stipulated application and development of new high-strength alloys. However, one of the main obstacles on the way to industrial applications of such alloys is their poor machinability. In the recent past, a non-conventional machining technique known as ultrasonically assisted turning (UAT) was introduced; in it low-energy high-frequency vibration is superimposed on movement of a cutting tool. UAT has been used to demonstrate several advantages over conventional turning techniques, especially in the machining of high-strength engineering materials. In this work, three-dimensional finite element models are developed for both conventional and ultrasonically assisted turning techniques in a commercial code MSC Marc/Mentat. The models were used to investigate the effect of vibration on cutting forces and temperature levels in a cutting region for various cutting conditions. Comparisons of simulations with experimental results demonstrate their predictive capability.