OBJECTIVES In this study, we aimed to determine the causes of overcrowding in the Emergency Department (ED) and make recommendations to help reduce length of stay (LOS) of patients in the ED. METHODS We analyzed the medical data of patients admitted to our ER in a one-year period. Demographic characteristics, LOS, revisit frequency, and consultation status of the patients were determined. RESULTS A total of 163,951 patients were admitted to our ED between January 1, 2013, and December 31, 2013. In this period 1,210 patients revisited the ED within 24 hours. A total of 38,579 patients had their treatment in the observation room (OR) of the ED and mean LOS was found to be 164.1 minutes. Cardiology was the most frequently consulted specialty. Mean arrival time of the consultants in ED was 64 minutes. CONCLUSIONS Similar to EDs in other parts of the world, prolonged length of stay in the ED, delayed laboratory and imaging tests, delay of consultants, and lack of sufficient inpatient beds are the most important causes of overcrowding in the ED. Some drastic measures must be taken to minimize errors and increase satisfaction ratio.