In this study the effectiveness of vibratory stress relieving (VSR) treatment on the residual stresses of axially welded steel tubes made of mild steel was investigated. Residual stresses of the tubes were measured before and after the VSR treatment by Barkhausen noise and X-ray diffraction. Slight, inhomogeneous stress reduction was observed in some of the tubes in the vicinity of the weld seam. Despite of this slight stress reduction, the VSR treated tubes distorted approximately the same amount as untreated tubes during machining. The mechanism behind the observed stress reduction is discussed.