The number of US individuals affected by dementia is expected to rise significantly during the next decade, as the age of the population continues to increase. To this end, we evaluated the rhesus macaque as a model of human aging by performing cross-sectional T1-weighted structural MRI brain scans of male and female animals across a wide age range. Our goal was to assess volumetric differences due to sex and age (N=74; 37 males, aged 5-29 years, 37 females aged 6-32 years).