The ability of a group of adults with high functioning autism (HFA) or Asperger Syndrome (AS) to distinguish moral, conventional and disgust transgressions was investigated using a set of six transgression scenarios, each of which was followed by questions about permissibility, seriousness, authority contingency and justification. The results showed that although individuals with HFA or AS (HFA/AS) were able to distinguish affect-backed norms from conventional affect-neutral norms along the dimensions of permissibility, seriousness and authority-dependence, they failed to distinguish moral and disgust transgressions along the seriousness dimension and were unable to provide appropriate welfare-based moral justifications. Moreover, they judged conventional and disgust transgressions to be more serious than did the comparison group, and the correlation analysis revealed that the seriousness rating was related to their ToM impairment. We concluded that difficulties providing appropriate moral justifications and evaluating the seriousness of transgressions in individuals with HFA/AS may be explained by an impaired cognitive appraisal system that, while responsive to rule violations, fails to use relevant information about the agent's intentions and the affective impact of the action outcome in conscious moral reasoning. (Contains 2 tables and 2 figures.)