In this theoretical note, possible neural causes of episodic memory impairment in individuals with ASD and currently normal intellectual and linguistic function are considered. The neural causes most commonly argued for are hippocampal or prefrontal cortex dysfunction, associated with impaired neural connectivity. It is argued here that a hippocampal dysfunction hypothesis is weakened by differences in cued recall and paired associate learning in individuals with ASD compared with individuals with developmental or acquired hippocampus-related amnesia, and that recent findings on patients with posterior parietal lesions (PPC) offer a better fit with the dissociation between free and cued recall observed in ASD. The PPC forms part of the default system subserving mindreading, among other functions, and an association between PPC dysfunction and memory impairment in ASD is consistent with recent suggestions that neural disconnectivity within the default system underlies behaviours diagnostic of ASD.