The primary purpose of the research is exploring the relationship between five fundamental leadership styles: self-management leadership, transformational leadership, transactional leadership, consideration and initiating structure- with two main phases of knowledge management procedure. The relationship between these leadership styles and two principle phases of the knowledge management process (i.e. knowledge creation and knowledge sharing) have been studied. The research method is descriptive, looking for correlation. The population of the research consists of 950 subjects including managers and senior experts of the NIOPDC. A sample of 270.subjects was selected. According to the research findings, there were significant relationships between these leadership styles and knowledge creation and knowledge sharing. Results also indicated that leadership styles accompanied with human interactions and participative processes are positively related to knowledge creation and knowledge sharing. These findings support the necessity of adopting more humanistic leadership styles for implementing knowledge management more effectively.