Background/Aims: In a questionnaire survey, we identified 36 (9%) of 417 Parkinson's disease (PD) patients with sleepwalking (SW); 72% of them also had a history of REM sleep behaviour disorder (RBD). We aimed to assess the clinical and polysomnographic characteristics of SW in PD and to compare them to patients with PD with and without a history of RBD. Methods: We performed video-polysomnography and detailed clinical examination in 30 PD patients from the above-mentioned survey: 10 patients with a history of SW, 10 patients with a history of RBD, and 10 patients with no history of either SW or RBD. Results: PD patients with SW had higher depression, anxiety and Hoehn & Yahr scores and lower activities of daily living scores than patients without a history of RBD but did not differ from patients with RBD. Patients with SW and RBD also had more often dyskinesia and hallucinations. By polysomnography, RBD was observed in 8 patients with SW and in all patients with a history of RBD. A total of 5 patients without a history of either SW or RBD had REM sleep without atonia without behavioural peculiarities. Conclusion: SW in PD is associated with depression, higher disease severity and functional disability. The simultaneous occurrence of SW and RBD (overlap parasomnia) in most patients suggests a common underlying disturbance of motor control during sleep in PD, with variable manifestations in different sleep stages.