We aimed to capitalize on the study of a large number of cognitively unimpaired late middle aged and older adults with two, one and no APOE-e4 alleles (Caselli et al., 2004) to characterize the ability of our automated hippocampal morphometry algorithm to distinguish between these three levels of genetic risk for AD and demonstrate its superiority to a commonly used hippocampal volume measurement. The gene discussed is APOE; the disease is Alzheimer disease.