Olfactory memory has some important distinguishing characteristics which may suggest its uniqueness in cognition. Evidence to support this hypothesis is the following: (a) odor memory is only slightly affected by the length of the retention intervals; (b) it is very resistant to retroactive interference (i.e., to forgetting produced by subsequent learning experiences); (c) odor memory presents a lower initial acquisition level compared to visual and verbal material (this led some authors to assume that odors are represented in memory as distinctive events and learned in an all or none fashion); (d) the relationship between odorants and words seems to be very weak; (e) no differences appear in recognition tasks for odorants learned intentionally or incidentally; (f) neither strategies nor interferences seem to affect recognition memory for odorants. Such peculiarities of odor memory will be discussed and tentatively integrated in a single model. The main assumption is that people lack a conscious representation for odorants, which are stored in memory at an implicit – unconscious – level of knowledge.