A prospective study was undertaken to describe the pattern of utilization of an observation ward in an emergency department (ED). During a 1-month study period, the following data were collected for all patients admitted to the observation ward: (1) patient demographics, (2) purpose of observation, (3) interventions at the observation ward, (4) disposal destinations, (5) disposal diagnosis, (6) outcome categories, and (7) duration of stay. A total of 12188 patients attended our ED and 1042 (8.51%) patients were admitted into the observation ward. An average of 34 patients was admitted into the observation ward each day. The age of the patients ranged from neonates to 94 years (mean age of 45.7 years, +/-25.7 SD). Sex distribution was almost equal. The diagnostic evaluation group was the largest (58%) followed by short-term therapy (38%) and psychosocial problems (3.5%). Of the 554 patients with a disposal diagnosis, 350 (59%) had their diagnosis clarified after the observation period. The percentage of patients admitted to the hospital was 23%. There were 42 chest pain and 46 trauma patients. The impact of an observation ward on the service in ED was discussed.