Subjective cognitive complaints (SCC) are currently considered to be a core feature of mild cognitive impairment (MCI). Yet the implications of including or excluding subjective complaints has not been previously considered. The key questions are how many healthy people complain of SCC compared to those with MCI? How is the epidemiology of MCI affected by the requirement for SCC? How is the prognosis of MCI influenced by SCC? and how should SCC be defined and measured? Findings to date suggest that subjective complaints are one of many variables that comprise risk in individuals with MCI. Individuals who do not have subjective complaints and might not qualify under current definitions of MCI may still have a disorder that is of clinical significance. Despite a close association, SCC may be neither necessary nor sufficient for a diagnosis of either MCI or dementia.