This work presents the optimization of process of car shell painting in FCA Serbia Ltd. by using the world class manufacturing (WCM). In order to show the advanced Kaizen within the pillar "Focused improvement" we have taken an example of problems in the production of a passenger vehicle "Fiat 500L" which is reflected in an inadequate colour match during serial production. The anticoincidence in the process of painting the shell of a vehicle was eliminated by Kaizen method. The analysis of vehicle shell painting process improvement was carried out by DOE, the verification of the proposed activities was completed, the experiment factor was identified, a hypothesis testing was conducted, all results were viewed and the process of verification and optimization was completed.