Objective of the master thesis was to identify the issue of the quality improvement by applying selected methods and tools in the selected enterprise, through the synthesis of theoretical and practical knowledge. The main goal of our thesis was to implement the Six Sigma method into the practice of a manufacturing enterprise ESTE s. r. o. Description of the selected enterprise and an assessment of its quality state-of-the-art were the starting points in the thesis processing. In the practical part, we followed the steps of the DMAIC cycle using the tools applied in Six Sigma. At the beginning, we defined the problem product and its production process. Subsequently, following the data we determined the capability of the process by the measurement, and finally, using the analysis we identified the possible causes of faulty pieces production. Based on the outcomes we proposed and implemented the necessary corrective measures, which subsequently affected the overall quality of production in positive way.