The K variant of the butyrylcholinesterase gene (BChE) was recently found to occur at an increased frequency in a late onset Alzheimer's disease (AD) population, specifically in individuals carrying the epsilon4 allele of the apolipoprotein E (APOE) gene. This suggested synergy between these two genes resulting in an increased risk of late-onset AD. We have genotyped 62 community-based and 329 clinic-based AD cases, and 201 community-based controls at BChE and APOE and find no independent association between BChE and AD nor interaction with APOE in risk for AD in either our clinic or community-based samples.