The oxidation of stainless steels 304 and 304L during hot rolling is studied in this paper. Results show the oxide scale thickness decreases significantly with an increase of reduction, and the oxide scales of both 304 and 304L stainless steels were found more deformable than the steel substrate. Surface roughness shows a complicated transfer during the hot rolling process due to the complexity of oxide scale characteristics. Also, surface roughness decreases with an increase of reduction. The friction coefficient increases with reduction in all cases, and the increase is more significant in the case of the 304 stainless steel than that of 304L stainless steel.