Sleep disorders are common and affect sleep quality and quantity, leading to increased morbidity. Patients with sleep disorders can be categorized as those who cannot sleep, those who will not sleep, those with excessive daytime sleepiness, and those with increased movements during sleep. Insomnia, defined as difficulty initiating or maintaining sleep that results in daytime impairment, is diagnosed using history findings and treated with cognitive behavior therapy, with or without sleep hypnotics. Restless legs syndrome is characterized by an urge to move the legs that worsens with rest, is relieved by movement, and often occurs in the evening or at night. Restless legs syndrome is treated based on the frequency of symptoms. Narcolepsy is characterized by excessive sleepiness, cataplexy, hypnagogic or hypnopompic hallucinations, and sleep paralysis. It is diagnosed using a sleep log or actigraphy, followed by overnight polysomnography and a multiple sleep latency test. Narcolepsy is treated with stimulants, such as modafinil; selective serotonin reuptake inhibitors; or gamma hydroxybutyric acid (sodium oxybate). Patients with snoring and witnessed apneas may have obstructive sleep apnea, which is diagnosed using overnight polysomnography. Continuous positive airway pressure is the most common and effective treatment for obstructive sleep apnea. Rapid eye movement sleep behavior disorder is characterized by increased muscle tone during rapid eye movement sleep, resulting in the patient acting out dreams with possible harmful consequences. It is diagnosed based on history and polysomnography findings, and treated with environmental safety measures and melatonin or clonazepam.