In 2013, a version of the Diagnostic and Statistical Manual of Mental Disorders (DSM), having number 5, was published. The DSM is a textbook which aims to present diagnostic criteria for each psychiatric disorder recognized by the U.S. healthcare system. The DSM-5 comprises the most updated diagnostic criteria of psychiatric disorders as well as their description, and provides a common language for clinicians to communicate about the patients. Diagnostic criteria of the DSM-5 have been popular all over the world, including countries where the ICD-10 classification is obligatory, and are widely used for clinical and neurobiological research in psychiatry. In this article, two chapters of the DSM-5 pertained to mood (affective) disorders are presented, such as “Bipolar and related disorders” and “Depressive disorders” replacing the chapter titled “Mood disorders” in the previous version of DSM-IV. The aim of this article is to discuss a structure of new classification, to point out differences compared with previous version (DSM-IV). New diagnostic categories, such as e.g. disruptive mood dysregulation disorder or premenstrual dysphoric disorder were depicted as well as some elements of dimensional approach to mood disorders were presented.