Raynaud's phenomenon (RP) is a very common sign which can usually be seen across all medical specialties. It is characterized by episodic color changes of acral parts of the body (palor, cyanosis, rubor) lasting from a few minutes to hours, which are usually triggered by cold temperature and/or stress. The primary RP occurs alone, without concomitant diseases, is usually benign and has favorable prognosis. Secondary RP occurs in a variety of diseases with a very variable progression and prognosis, mostly unfavorable one due to the development of ischemic tissue necrosis and gangrene. This work provides a comprehensive overview of the history, current knowledge about the epidemiology and pathogenesis and the recommended evaluation and treatment of RP.