Six Sigma as the continuation of comprehensive quality management TQM is of interest to many enterprises. Unfortunately, not everybody successfully implements quality improvement projects using Six Sigma tools. This approach requires proper preparation in many areas of the company’s operation, including: organization of processes, establishing measures, employee engagement and creating conditions for continuous improvement. The goal of the article is to present on the case study the idea of using the organizational maturity model for production management to assess a readiness of organization to implement Six Sigma. The case study presents a company maturity level diagnosis and a successful project of quality and productivity improvement using the Six Sigma concept, confirming that the organization’s maturity model is the appropriate tool for assessing multi-faceted preparation for successful implementation of Six Sigma projects.