Patients with Parkinson's disease have nonmotor symptoms (NMS) that, although poorly considered, have an impact on their quality of life. In contrast, the effect on disability is not systematically evaluated. Adult patients were consecutively enrolled and administered the Non-Motor Symptoms Questionnaire and the WHO Disability Assessment Schedule. Student's t-test was used to assess the difference in the disability score between patients declaring and not declaring NMS. In total, 86 patients were enrolled and reported a median of nine NMS. Patients reporting symptoms in cognitive, emotional, cardiovascular, and sleep functions, as well as those reporting more than nine symptoms as a whole, also reported higher disability levels. The presence of NMS, including little evaluated areas connected to cardiovascular and sleep functions, negatively impacts disability in patients with Parkinson's disease.