Emergency department (ED) acts as a feeder to many hospitals as it determines a large proportion of admissions. ED also acts as a buffer zone for many patients who cannot get care in other institutions due to insurance issues. Most hospitals are trying to invest heavily on their EDs, but cannot meet patients’ satisfaction in terms of cost and quality of care. There is great need for EDs to understand customers’ expectation given the rising cost of healthcare. The focus of this study is at an ED center in Bowling Green Kentucky, using theory of constraints (TOC) thinking process application tools to capture in detail the core and apply TOC to resolve the problems identified. The research was able to identify the core problems as: Backlog of patients in ED, delay in making dispositions, and patients waits on ED to transfer to another facility. The research was able to address the core issues by answering three questions: What to change? This was answered by the CRT “ED unable to meet patients’ expectation.” What to change to? This was answered by the EC “Positive patient outcomes”. How to change? This was answered by the FRT by using injections that resulted to “ED is able to meet patients’ expectations most of the time."