Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by complex motor behaviors and REM without atonia. RBD shows diverse clinical manifestations, ranging from typical violent dreamenacting behaviors to relatively subtle limb movements. Sleep disorders such as obstructive sleep apnea (OSA) and nocturnal seizure that mimic RBD symptoms are referred to as pseudo-RBD. We describe a patient who showed an atypical clinical presentation of pseudo-RBD associated with severe OSA. Polysomnography with a full 10–20 electroencephalography montage was useful for accurate diagnosis.