Patients with Alzheimer's disease (AD) exhibit impaired performance on tests of recall and recognition. Recall and recognition require conscious, or intentional, recollection of a previous experience and have been labeled explicit memory tests. Recently, researchers have studied the performance of AD patients on tests that do not require conscious recollection of previous learning so-called implicit memory tests. This paper describes the rationale for, and results of implicit-memory research in patients with this type of dementia. It appears that studies of implicit memory have produced mixed results. Implications of research into the implicit-memory abilities of AD patients will be discussed.