The median nerve cross-sectional area in patients with PD (10.71 ± 2.79 mm(2)) was significantly larger than that in the control group (7.40 ± 1.05 mm(2); P<.05). However, there was no significant difference in median nerve electrodiagnostic findings between the PD and control groups. The median nerve cross-sectional area was associated with the severity of the tremor but not with the Unified Parkinson's Disease Rating Scale motor score.