The decline in self-related memory in ASD was investigated by using encoding, forgetting, and source monitoring. Participants memorized action sentences verbally, observationally, or by enacted encoding. Then, they underwent recall, recognition, and source monitoring memory tests immediately and 1 week later. If the information were properly encoded, memory performance in the enacted encoding would be the highest (enactment effect). The result of memory tests in ASD and TD people showed that enacted encoding was superior. However, recall and source monitoring in ASD was significantly lower than in TD, which was not the case for recognition and forgetting. These results suggest that the decline in memory of self in ASD is associated with a deficit in memory reconstruction and source monitoring.