Background: The rate of patients who arrive at the Emergency Department (ED) but leave before being seen (LWBS) is considered an important marker of the quality of care. Objectives: To evaluate the rate of LWBS at ED in Al Wakra Hospital (AWH) and to identify predictive factors associated with LWBS. Methods: This was a retrospective study of patients who left the Emergency Department without being seen by physicians between January 1, 2015 and May 31, 2015. Factors associated with LWBS such as the age, sex, time of the day, day of the week, median ED waiting times and common ED presentation were analyzed. Results: Out of 95,375 patient visits; there were 426 cases of LWBS over the 5-month period. The highest rate of LWBS was seen on the month of March. Independent factors associated with LWBS patients include patients who are middle age (19-43 years), female (56%), and patients being presented at non-critical areas (100%), night shift visits (46%), on weekend (52.8%). Musculoskeletal complaint was the most frequent complaint associated with LBWS (31%) and the median waiting time was 45 minutes among LBWS patients. Conclusion: The rate of patients leaving without being seen at ED in AWH is very low. More investigations need to be conducted to improve LWBS rate during night and weekends.