Providing the Success of Six Sigma by Proper Project Identification and Selection: Comparison Study between Slovenia and the UK Results of Six Sigma projects are related to company performance. Successful Six Sigma projects increase customer satisfaction and have many other positive effects on organisations. Success of Six Sigma projects is related to key management decision about how to identify potential projects and which projects to select for final implementation. This research is oriented toward the study of tools used in the phase of Six Sigma project identification and criteria used in the phase of Six Sigma project selection. The purpose of this research is to compare results from manufacturing sector in Slovenia and the UK. Results of this study indicate that management within the organisations tend to identify potential Six Sigma projects with the use of different tools, such as: brainstorming (Slovenia and UK.), followed by Critical To Quality tree (UK.), and interviews and customer visits (Slovenia). Further, the results show that the final decision about Six Sigma projects selection in the UK and Slovenia include different criteria, such as: customer benefit (Slovenia and UK), finance impact (UK) and connection to business strategy (Slovenia). Many companies in the UK as well in Slovenia combine the use of tools and balanced selection criteria at the same time.