Temperature and forces in friction stir processing (FSP) induced by process input parameters play a critical role in successful welding. In this investigation, the effect of the process parameters on the axial and longitudinal forces and temperature history of the process were investigated. The temperature distribution during the FSP was determined by placing thermocouples in the workpiece and measuring the temperature during the process. The tool forces were investigated experimentally using an especially designed load measuring system. The pin shape, rotational speed and traverse speed were the parameters taken into consideration. It was observed that increase in tool traverse speed or decrease in rotational speed leads to increase in both tool axial and longitudinal forces.