IntroductionAccording to the Oxford Dictionary, a leader is defined as “the person who leads or commands a group, organization or country” (Oxford Dictionaries, 2013) . Although there is a definition of what a leader is, people still have different ideas about what a leader should be and how they should act. There has never been a concrete idea of ​​what a leader is; the only thing we know is that this person is the unit manager. We look at the characteristics of people we consider leaders and use those attributes to compare other people to see if they are capable of being as good or better than the aforementioned leaders. We must keep in mind that in different situations, leaders must perform different tasks, which indicates the need for different qualities. This is especially true in the hospital or other health care settings. Although it is similar to other companies, it stands out because of the continuous change it must undergo thanks to new technologies, technical innovation and new medical treatment plans developed every day. In this article, I will discuss complex adaptive systems, particularly as they relate to the healthcare setting, as well as the leadership needed for these systems. What is a complex adaptive system (CAS)? A complex adaptive system is an entity of networks and connections. It can “learn and adapt to change over time,” which can alter the “structure of the system” (Clancy, Effken, Pesut, 2008). It contains twelve elements: autopoesis or self-regeneration, open exchange, participation in networks, fractals, phase transition between order and chaos, search for fitness peaks, nonlinear dynamics, sensitive dependence, attractors limiting growth, strange attractors of 'emergence... ... middle of article ......Eds.), Nursing, Care and Complexity Sciences (pp. 325-338). New York: Springer Publishing Company. Clancy, TR, Effken, JA and Pesut, D. (2008). Applications of complex systems theory to nursing education, research, and practice. Nursing Perspectives, 56(5), 248-53.Crowell, D.M. (2011). Leadership in complex nursing and health care systems. In AW Davidson, MA Ray, & MC Turkel (Eds.), Nursing, care, and complexity sciences (pp. 199–210). New York: Springer Publishing Company. Oxford Dictionaries. (2013). leader: definition of leader in the Oxford – American English (United States) dictionary. Retrieved December 7, 2013 from http://www.oxforddictionaries.com/us/definition/american_english/leaderStackman, RW, Henderson, LS and Bloch, DP (2006). Emergence and community: The story of three complex adaptive entities. Emergence: complexity and organization, 8(3), 78-91.