Emergency department overcrowding is a critical problem nation-wide. A survey by the Lewin Group in 2002 found that 90 percent of Level 1 trauma centers and hospitals with more than 300 beds reported being over capacity. Although ED overcrowding has many causes, external factors are most commonly blamed--too many patients, lack of inpatient capacity, inappropriate use of the ED, the Emergency Medical Treatment and Active Labor Act (EMTALA), lack of primary care availability, and lack of access to health care for the uninsured. In this article, we describe a series of changes that were implemented in the ED of a regional medical center. Those changes improved operational efficiency, expedited patient care, and reduced ED overcrowding. The changes focused on patient input, throughput, and output. In terms of input, we revamped the triage and admission processes. To improve throughput, we modified the physical layout of the urgent care area to maximize efficiency in staff movement and communications, changed staffing patterns to match anticipated patient volume, and revised our policies regarding exchanges with the radiology staff. To facilitate patient flow out of the ED, we identified the causes of delays in discharges and admissions, instituted the practice of flagging the charts of patients ready for discharge, and implemented admission orders to decrease patient waiting times. Improving patient throughput increases ED efficiency, and thus capacity, in terms of the number of patients that can be treated over a given time period, and it promotes the cost-effective use of institutional resources. Decreased waiting times should ultimately lead to increased patient satisfaction and better patient care.