The 2014 Russian - Ukrainian crisis and Russian military activities in the crisis, that changed the security paradigm in Europe, reopened the debate on the characteristics of post Cold War conflicts, which have been associated mainly with terrorism and civil war. The post-Cold War conflicts produced new warfare theories, including “low intensity warfare”, “fourth generation warfare” or “compound warfare”, followed by “hybrid warfare,” the term used by the West for Russian military activities in Crimea and eastern Ukraine. This paper first outlines the basis of warfare principles and characteristics described in official military doctrines, and describes post Cold War warfare theories focused mainly on the evolution of hybrid warfare theory. It basically examines Russian military activities within the framework of warfare doctrines in official military documents. It will be argued that hybrid warfare, like the other theories that describe post Cold War conflicts, does not constitute a new form of warfare.