This research study starts with the hypothesis that the personality traits of managers influence their leadership styles. Personality traits are taken from the model Big Five (McCrae and Costa) since it is one of the most dominant models of personality in modern psychology. Management styles (leadership) were investigated within the theories of transformational and transactional leadership, including laissez-faire style (Bruce Avolio & Bernard Bass). The research was conducted with 160 lower-level, middle-level and high-level managers in Serbia, employed in private and public sectors. From the questionnaire the NEO Personality Inventory (Serbian version, Kostić, P. 2002), and with the analysis of the main components, five dimensions of personality have been extracted: extraversion, neuroticism, conscientiousness, agreeableness and openness to experience. From the shorter version of Multifactor Leadership Questionnaire, three factors of leadership have been extracted: transformational, transactional and laissez-faire. The relationship between the received factors was checked by Pearson`s correlation coefficient and by multiple regression analysis. The received information showed that there is a statistically significant relationship between personality traits and leadership styles, and the most dominant relationship is between the transformational leadership style and extraversion (in a positive sense) and neuroticism (in a negative sense).