Insomnia is the most common sleep disorder characterized by difficulty in initiating or maintaining sleep, and consequent disturbances in daily functioning. It affects approximately 10 – 20 % of the population, especially women and the elderly. It can occur as a short-term or chronic condition, or related to other diseases. The exact pathophysiological mechanism of non-organic insomnia has not been fully discovered yet. It has been proven that insomnia and lack of sleep have a lot of negative effects on an individual’s health, such as an increased risk of developing cardiovascular diseases, obesity, type 2 diabetes, and injuries. Insomnia is often associated with various psychiatric conditions such as depression, anxiety disorder, bipolar disorder and psychosis. The diagnosis is based on a detailed medical history, sleep history, and subjective experience of affected individuals. Depending on the need, other diagnostic methods such as various available scales and sleep questionnaires or polysomnography can be used. The first-line treatment for insomnia is a cognitive-behavioral therapy (CBT). It consists of psychoeducation on sleep hygiene, relaxation training, stimulus control therapy, sleep restriction therapy and cognitive therapy. If CBT is unavailable or ineffective, different types of pharmacotherapy such as benzodiazepines, BZRAs, antidepressants or melatonin may be used. Due to the numerous and frequent side effects of benzodiazepines and BZRAs, especially in the elderly population, they are only recommended as a short-term treatment for insomnia. Melatonin is a much safer drug, but further research on its clinical efficacy is required. In long-term treatment, a combination of cognitive-behavioral therapy and pharmacotherapy is recommended. Occasional cessations of hypnotic pharmacotherapy are important, combined with the continuation of cognitive-behavioral therapy.