Disorders of arousal (DoA) and sleep-related hypermotor epilepsy (SHE) are sleep-related events characterized by complex, often bizarre, and violent behaviors. DoA are involuntary motor manifestations of different complexity occurring during an incomplete awakening from NREM sleep. SHE is a focal epilepsy characterized by stereotyped hyperkinetic or/and asymmetric tonic/dystonic seizures usually arising from NREM sleep. Even if many aspects regarding DoA and SHE have been recently clarified, the differential diagnosis remains challenging, since DoA and SHE share some semeiological features and genetic background. The clinical history, collected from the patient and his/her witness, represents the first and common milestone in the diagnosis. Validated questionnaires constitute suitable screening tools that could guide further analysis. The worldwide availability of homemade video recording has increased the possibility of adding more objective information to the clinical history alone. The confirmed diagnosis relies on video-polysomnographic (vPSG) recording although it requires time, economic resources and specific skills for the analysis. In this review we propose a simple diagnostic algorithm for the differential diagnosis between DoA and SHE in adults based on the most updated knowledge, from the simpler tool to the most specific and tailored one.