BACKGROUND AND AIM: Νon-motor symptoms in Parkinson's disease (PD) are very common and contribute to the severity of patient's disability. We evaluated the frequency of nonmotor symptoms in patients with PD and we explored the influence of disease characteristics on the presence of these symptoms.PATIENTS AND METHODS: One hundred sixty six patients and sixty six matched controls were enrolled in the study. The Non-Motor Symptoms Questionnaire (NMSQuest), a 30-item self-completed questionnaire, was used for the evaluation of nonmotor symptoms.RESULTS: Non-motor symptoms were more common in PD patients than controls. Mean ± SD NMSQuest score was 6.76 ± 4.22 in PD patients and 5.44 ± 4.45 in controls (p=0.035). The more common non-motor symptoms in PD patients were urinary urgency (54.3%), nocturia (51.8%), constipation (45.7%) and sadness (42.1%). There was a correlation between NMSQuest score and severity of the disease.CONCLUSION: Non-motor symptoms in PD are too important to remain undetected. By incorporating into every day practice the use of suitable, reliable questionnaires, we will be able to facilitate detection and management of these symptoms.