Yes and no....you can use them in TKD, but then you aren't practicing straight TKD. If you have to use your boxing skills in TKD (which punches and stances far differently from everything I know) in TKD, how can it be the ULTIMATE art? Why wouldn't boxing be the ultimate martial art, if you just use TKD kicks? TKD is a good kicking art, but otherwise, it is SEVERELY lacking. Even in kicking, the great majority of the kicks are impractical/desperation (spinning back kick, axe kicks, etc)