Lean manufacturing refers to a manufacturing paradigm based on the fundamental goal of the Toyota Production System-continuously minimizing waste to maximize flow. Many organizations recognize the importance of becoming lean but most of them achieve the limited improvement in the part of entire processes. This results from the fact that many organizations not only understand lean manufacturing as just a tool for the cost reduction or productivity improvement or no inventory but also sporadically implement improvements without linking their efforts to an overarching strategy and quality management system as well. Many organizations are doing lean without necessarily becoming lean. All the elements of lean manufacturing system should be implemented based on the process approach considering mutual interactions among them to minimize waste to maximize flow. In this point of view, I am positive that ""ISO 9004:2000 Quality Management System-Guidelines for Performance Improvement"" based on process approach could provide a fundamental structure with the organizations toward lean enterprise. I hence would like to introduce a self-assessment checklist to help the organizations develop and assess ISO 9004:2000 based quality management system linking to their overarching lean strategy toward becoming lean.