Abstract: This paper presents a brief overview of Lean and Six Sigma use and success in the oil and gas industry by using principles of enhanced productivity, safety and environment as well as process quality management in a well-defined framework. A literature review is also presented, including negative and positive opinions about Six Sigma implementations in industry. Lessons learned from successful implementation of Lean in oil and gas industry are analyzed and summarized. A positivistic approach with case studies of Lean as practiced in some major oil and gas companies in Abu Dhabi is being used. Methodology and process of application of Lean is also described. The study shows the importance of Six Sigma and Lean applications in three of the most important areas in oil and gas: Service quality drilling operations, customer satisfaction, and supply chain. Two successful case study projects are provided with step by step details and are organized around three main parts: the problem, the methodology and the lessons learned. Despite some misconception that some managers have about the implementation of Lean, it will stay the most efficient methodology to apply in the oil and gas business. Success of Lean depends also on top management decisions. Also, the application of these methodologies when applied successfully to projects can produce rewarding results. This paper will outline successful applications of Lean and Six Sigma by two major oil and gas industries in the United Arab Emirates.