Different aspects of episodic long-term, short-term and implicit long-term memory were investigated in subjects who strictly fulfilled the criteria for the amnestic form of Mild Cognitive Impairment (a-MCI). Results showed normal short-term memory abilities in these subjects, while each of the episodic long-term memory indices explored showed poorer results in a-MCI subjects with respect to normal controls. Although some episodic memory functions were relatively well preserved, others appeared to have deteriorated to a level comparable to that of mild AD patients. The finding of an extensive impairment of all memory functions depending on hippocampal structures in a population with a high risk of developing dementia is strongly supportive of the hypothesis that a pure amnesic syndrome characterizes the preclinical phase of AD.