Control chart is one of the statistical process control tool that its use is for monitoring and controlling variations in the production process. It enables one of variation sources - the special cause - to be identified, signaling at the quality manager that the process involved might be in a state of “statistically out of control”.  This particular state of production process jeopardises quality of the products produced. Clearly, the control chart is a prominent tool in the statistical process control. Despite this fact, the control chart suffers from inability to identify the true root causes of a problem behind the presence of the special cause. This paper reports on the result of research on developing a novel tool of root cause analysis designated for the control chart. It also reports of the successful result of validating the tool on a case study company in Indonesia.