The experience obtained from the human hand allografts (HHA) performed to date suggests that the skin is a priviledged target of allograft rejection in this setting. The aim of this study was to establish a pathological score for assessing the severity of HHA rejection. The pathological slides of 89 skin biopsies obtained from the allografted limbs of six HHA recipients from day 0 to 5 years post-graft were retrospectively examined. According to the severity of the pathological changes observed, the following grades of rejection are proposed: 0: no rejection, I: mild rejection, II: moderate rejection, III: severe rejection, IV: very severe rejection. This grading system can be used as a basis for monitoring allograft rejection and for assessing the effects of the immunosuppressive treatment aiming at reversing HHA rejection; it can also be used for monitoring rejection of other skin-containing CTA.