Oil and Gas, Petroleum Refining Industry is undergroing through significant Business Challenges, Transformation and Consolidation. Refinery Business Economics has been encountering increased challenges due to significant variations in the market dynamics. Refining Optimization has acquired renewed importance in the past decade and optimization of the existing facilities has become a key component in the overall Business Strategy. Operational Excellence forms the necessary attribute for Optimal Business Performance of the Progressive Companies. Operational Excellence and Business Excellence are the key focus areas for Petroleum Refining Industry in the Middle East and Other Regions. Operational Excellence and Business Excellence requires best in class performance in all the functional areas of relevance to the Business. Operational Excellence and Business Excellence are closely inter- related and complement one another towards superior Business Performance. Operational Excellence Groups in the company deal with activities that would help to inculcate culture of excellence and help in the effective implementation of continuous improvement activities across the company facilities. Periodic Assessment of Operational Excellence is extremely important for identifying the status and take necessary corrective measures /additional measures towards continuous improvement. ADNOC Refining has been involved in Operational Excellence activities and Business Excellence activities for the past two decades with and without the involvement of external consultants. This paper deals with key aspects of Operational Excellence review and methodology of systematic implementation, key challenges, and experiences of first of its kind simultaneous implementation across ADNOC Refining Operating Facilities.