In this paper, an analysis of electric resistance spot welding between micro-alloyed steel sheets having 1 mm thickness and TRIP 800 (transformation induced plasticity) steel sheets having 1.5 mm thickness was made. Couples of steel sheets are used in automobile industry. Steel pairs were joined by using resistance spot welding as overlap joint. A timer and current controlled resistance spot welding machine had pneumatic application mechanism and 120 kVA capacity. Preparation of specimens by spot welding was performed using different cycles ranging from 5 to 30 cycle and welding currents ranging from 8.5 to 16.5 kA by rise of 0.5 kA. The electrode force was kept constant at 6 kN. The prepared welding specimens were exposed to tensile-peel tests and the obtained results were supported by diagrams. Finally, appropriate welding parameters were advised to the users.