Rapid eye movement (REM) sleep behavior disorder (RBD) is a sleep disorder characterized by loss of normal muscle atonia during REM sleep with recurrent dream enactment and excessive motor activity. It is a frequent feature in patients with Parkinson's disease (PD) and other alpha-synucleinopathies, and can occur at any stage of the disease. RBD could be considered a premotor clinical manifestation, and can antedate by many years the motor symptomatology. The prognostic value of RBD for the risk of developing PD still needs to be established. This review article focuses on the clinical aspects, screening and diagnostic criteria as well as therapeutic aspects of RBD in PD patients. Pathophysiological pathways are also briefly reviewed.