Background: The observation ward (OW) allows patients to be reassessed and monitored before deciding either to admit or to discharge them. This is a six-month descriptive cross-sectional study conducted in the observation ward of the Emergency Department (ED) of Hospital Universiti Sains Malaysia, Kelantan. The objective of this study was to examine the demographic characteristics and clinical profiles of adult observed patients and to determine the effectiveness of OW management. Methods: Patients were selected randomly by convenience sampling. One hundred and twenty-four patients were included in the study. The mean age was 40.3 ± 18.5 years (95% CI: 37.2 to 43.8). Results: Among the common clinical problems were abdominal discomfort (23%), diarrhoea and vomiting (13%) and fever (13%). Reasons for OW admission included diagnostic uncertainty (63%) and short course of treatment (33%). The mean length of stay was 4.1 ± 1.8 hours (95% CI=3.8 to 4.4 hours). Most of the patients (85%) were discharged. Conclusions: The OW of HUSM is effective in managing adult patients as determined by the hospitalisation rate and the length of stay.