Rehearsal strategies of adults with autism spectrum disorders (ASDs) and demographically matched typically developed (TD) adults were strategically manipulated by cueing participants to either learn, or forget each list word prior to a recognition task. Participants were also asked to distinguish between autonoetic and noetic states of awareness using the Remember/Know paradigm. The ASD group recognised a similar number of to-be-forgotten words as the TD group, but significantly fewer to-be-learned words. This deficit was only evident in Remember responses that reflect autonoetic awareness, or episodic memory, and not Know responses. These findings support the elaborative encoding deficit hypothesis and provide a link between the previously established mild episodic memory impairments in adults with high functioning autism and the encoding strategies employed.