In this study, we used high-resolution 7Tesla MRI to study whether subthalamic nucleus (STN) characteristics, such as volume and fractional anisotropy (FA), can be used as a biomarker for Parkinson’s Disease (PD). 7Tesla MRI data were acquired for twenty-nine PD patients and twenty-one controls. Right STN volume was significantly lower in PD patients and it was negatively correlated with the UPDRS motor score. The PD group also had significantly decreased FA values in bilateral STN. To our knowledge, this is the first study to report differences in volume and FA of the STN between people with PD and controls.