The present work was undertaken to compare the mechanical characteristics of AA6061-O aluminum plates welded using friction stir welding (FSW) and metal inert gas (MIG) techniques. Plates from AA6061-O plates were welded using the aforementioned techniques using different process parameters. A comparison between the impact toughness and tensile strength of FSW and MIG was carried out. Moreover, the effect of FSW and MIG process parameters on these properties was investigated. The results revealed that the FSW samples exhibited significantly higher impact toughness and tensile strength when those welded using MIG technique. For FSW, increasing the tool rotational speed reduces slightly the impact toughness, but increases the tensile strength of AA6061-O weldments. While increasing the welding speed increasing slightly both of the tensile and the impact toughness of FSW specimens. For MIG welded specimens, increasing the welding current reduces the impact toughness, but increases the tensile strength of the AA6061-O weldments. However, increasing the welding voltage reduces slightly both of the tensile strength and impact toughness of the AA6061-O weldments .