The mix of Lean and Six Sigma was created in 2002. For the first time by M. George in his work entitled “Lean Six Sigma (LSS): Combining Six Sigma with Lean Speed”. The LSS means merge of both above mentioned terms are as follows: • Lean: represents elimination of waste and to increase process efficiency; • Six Sigma: reduce deviation from a certain dimension through process stability and achieve process without defects. The most important feature of Six Sigma methodology incorporated into Lean Six Sigma is to try to measure and decrease variations, that is, deviations inside the process, i.e. to do things better, decrease time of cycle, i.e. to do things faster and to increase utilization rate, i.e. to do things cheaper. Lean Six Sigma concept in following four words: teams, process, customers and benefit, explains best meanings of this concept. The interaction among costs in development phase and their influence on the future total product costs is clearly strong. It is so clear that design with 5% influences 70% of total costs, whilst the material which has value of 50% influences just 20% of production costs of the future product. This article is dealing with one aspect of bad quality product in application of Lean Six Sigma (LSS) concept, which is possible to use in metalworking sector. This article proves the using of LSS tools and its application in metalworking oriented company from Bosnia and Herzegovina in order to improve product quality during final machining and welding process.