There are an estimated 6.1 million Americans currently diagnosed with Alzheimer’s disease (AD) with this number expected to rapidly grow over the next 30 years. Delusions are reported in roughly one-third of individuals with AD ^{(Ropacki & Jeste, 2005)}. Delusions in AD are related to worse outcomes; greater caregiver burden, functional decline, and overall, worse general health (Murray et al., 2014). Current treatment options are limited given the health risks related to antipsychotics in the elderly (Creese et al., 2018). In the current study, we examined the relationship between APOE ε4 allele status, CA1 subfield volumes, and the presence of delusions in a combined Alzheimer’s disease dataset (OASIS and ADNI) in a two-prong fashion. First, we examined the moderating effect of APOE ε4 allele on the relationship of the CA1 volumes and delusions and MMSE scores, separately. Second, we examined the specificity of that effect by comparing CA1 volumes to other hippocampal subfields in a repeated measure model. Individuals with delusions had smaller right CA1 volumes than individuals without delusions but this was unrelated to APOE ε4 alleles. There was no significant moderation of the APOE ε4 alleles on the relationship between the CA1 subfields and the presence of delusions. There was a significant relationship between left CA1 volumes, APOE ε4 allele presence, and MMSE scores. These findings do not completely dissuade a subcortical relationship with delusions as no other notable differences between individuals with delusions and individuals without delusions were found in demographic information, genetic information, or cognitive measures. Future research is needed to examine the relationship between the hippocampus and delusions in other imaging capacities (e.g., longitudinal studies, functional connectivity) and along more detailed presentations of delusions.