The present study is focused on the mechanical properties of the deposited material which was extracted from welded region. This study explains the effect of the shielding gas composition on tensile behavior, R = - 1 fatigue response and various temperature impact test results of MIG welded low carbon steels. In tensile tests, the strength values are increased with increase of CO2 Content, whereas the ductility is decreased. In the fatigue tests, the fatigue strength and the number of cycles to failure enhanced as the content of CO2 increased. However, the impact toughness of the filler material is seriously influenced by the content of the shielding gas. An increase in CO2 content caused significant decrease in toughness values at all temperatures.