Abstract. This research is focus on the problems cause the assembly line stop in a Japanese automotive manufacturer in Thailand. The problem arose from not being able to supply parts to the assembly line in time and supplying wrong parts to the assembly line. Methods to resolve these problems involved the followings: 1) design new tag labels, 2) improve operations method and 3) redesign the parts storage layout and supply routes. The result showed that the time for transferring parts from the warehouse to the preparing area and the overlapped routes were reduced. Moreover, the supply accuracy from the preparation area to the assembly line was improved.