Lean Six Sigma is a proven process improvement methodology currently widely being employed across nearly every type of business and industry including numerous chemical companies. This paper describes the application of Lean Six Sigma methodology for manufacturing problem solving in a chemical plant. Examples and case studies for real chemical manufacture process trouble shooting will be described. A systematic problem solving process, DMAIC process (Define, Measure, Analyze, Improve and Control), was demonstrated from the point of view of the practicing chemical engineer.