Huntington’s disease (HD) is a genetic, neurodegenerative disorder caused by CAG repeat expansion in mutant huntingtin gene (mHTT) on Chromosome 4 and is characterized by degeneration of several brain regions, with the caudate nucleus and the putamen being the most heavily affected. Structural MRI was used to investigate the longitudinal striatal atrophy in a new rhesus macaque HD model, especially the reduction of rostral caudate volume. According to the longitudinal volumetric analysis, the delivery of 82Q mHTT to rhesus macaque striatum leads to a significant reduction in caudate volume. However, no such significant differences following delivery of 16Q mHTT model was observed. These data indicate that viral delivery of 82Q mHTT serves as a nonhuman primate model of Huntinton’s disease that reproduces neuropathological characteristics of the disease.