Knowledge management is a critical issue in today's business world. Knowledge is considered to be one of the most strategic resources of a firm and sources of competitive advantage. This paper identifies and ranks Critical Success Factors (CSFs) for implementation of knowledge management in the Iranian Energy Sector. Using the Analytic hierarchy process (AHP) method the relative quantitative weights of 8 of the major CSFs for implementation of knowledge management are identified, based on analyses with KM designers in the Iranian energy sector. The outcomes of the research designate that the critical success factors in the order of importance are: corporate culture, human and financial resources, strategy and leadership, structures and procedures, meso environmental factors, knowledge management process, macro environmental factors, technology and infrastructure.