<i>Aim:</i> To describe the distribution of apolipoprotein E (APOE) genotypes in a cohort of memory clinic patients. <i>Methods:</i> We included 749 memory clinic patients. Diagnoses were made in a multidisciplinary consensus meeting and the APOE genotype was determined. The community-based cohort of the Longitudinal Aging Study Amsterdam was used as control population (n = 2,233). <i>Results:</i> In the memory clinic sample, there were 173 patients with subjective complaints, 125 patients with mild cognitive impairment (MCI), 251 patients with Alzheimer disease (AD), 107 patients with another type of dementia, and 93 patients with another neurologic or psychiatric diagnosis. The APOE allele distribution differed among groups. There was no difference in the prevalence of the Ε2 allele, but there were differences in distribution of the Ε3 and Ε4 alleles. Compared with the control population (15%), the prevalence of APOE Ε4 was increased among patients with subjective complaints (22%), MCI (36%), AD (42%) and other types of dementia (25%). <i>Conclusion:</i> We observed an increased prevalence of APOE Ε4 in patients with MCI and subjective complaints. This finding is of great clinical importance as nondemented patients positive for APOE Ε4 could be identified as being at genetic risk of AD, and for that reason monitored more closely.