While in the past the country's development was based on the competitive advantage which had its foundations in cheap labour and natural resources, the international competitiveness has recently been achieved by the advanced conditions based on knowledge, innovation, developed infrastructure and high technology. It is obvious that when a national economy wants to improve its competitiveness, it should focus its efforts on entrepreneurship, its role in the development of the economy and the encouragement of private initiatives. Under the influence of global change, entrepreneurship is increasingly important and is increasingly perceived as a generator of social and economic development around the world. Entrepreneurship is primarily related to the creation of new business ventures and the achievement of positive business results, so it is necessary for companies to achieve a level of agility and entrepreneurial orientation that will contribute to the creation of competitive advantage. Entrepreneurial orientation promotes entrepreneurial initiatives through all levels of management while formulating and implementing entrepreneurial strategies. It is, therefore, crucial to determine whether the organisation’s leaders have knowledge and skills that would lead the whole organisation towards entrepreneurial orientation. Leadership is at the same time scientific discipline and practical skill related to the ability of an individual or organisation to lead or direct other individuals or organisations (Northouse, 2010). In mid-seventies of the last century, it was noticed that the implementation of organisational changes has been successfully carried out only in organisations under the leadership of highly capable leaders that have encouraged entrepreneurial orientation within organization. Based on this research, an approach of group dynamics has been developed which claims that the transformation leaders, as the authors (Bass i Avolio, 1993) call them, must have a vision, problem-solving skills and the ability to inspire followers to overcome the current demands or drive entrepreneurial orientation.The results presented in this thesis show to what extent the informational style of leadership is important in the process of creation, development and competitiveness of each organisation. The methodology used in this thesis is of a practical character and can be used for future procedures of determining the organisation's and leader’s ability to create competitive advantage. Different leadership development programs in organisations can be based on the development model of successful organisations that would have a direct positive impact on efficiency and the achievement and retention of competitive advantages on domestic and foreign markets. With that the existing entrepreneurial basis gets a new impetus for further developmental steps. In Croatia and worldwide, a significant part of the national economy is based on small and medium enterprises which should become the primary target group in the implementation of this leadership style.