Introduction: Emergency department (ED) plays a main role in the initial management of patients who are critically ill. These patients require intra-hospital transfer for continuation of care. Adverse events can occur during this short duration and the distance of intra -hospital transfer. The aims of this study were to determine the incidence of adverse events during intrahospital transfer from ED and to determine the factors associated. Methodology: This was a cross-sectional observational study done from November 2017 until December 2017 at ED Hospital Sultan Abdul Halim (HSAH), a 650-bedded tertiary hospital in the state of Kedah. All patients that were triaged to red zone, age 18 years and above, and involved in intra-hospital transfer to critical coronary unit, intensive care unit and wards were included. All cases were documented in proforma by the accompanying staff. Results: Among the 170 critically ill patients, only 29 patients (17.1%) experienced adverse events during intra-hospital transfer. The adverse events seen were hypotension (12.4%), desaturation (3.5%) and dislodged peripheral line (2.4%). Cardiorespiratory related diagnosis was the commonest presentation. Intra-hospital transfer during morning shift and evening shift has 79.5% (b=-1.59, OR=0.21, 95% CI: 0.06, 0.69, p=0.011) and 75.6% ((b=-1.41, OR=0.24, 95% CI: 0.08, 0.73, p=0.012) lesser odds of experiencing adverse events compare to night shift. Patients with vasopressor/inotropes had 9 times higher odds of experiencing adverse events during transportation, compared to patients with no vasopressor/inotropes (b=2.27, OR=9.70, 95% CI: 3.39, 27.72, p<0.001). Conclusions: Critical care patients who are involved in intrahospital transfer were at risk of adverse events such as hypotension, desaturation and dislodge peripheral line. Risk identification and maintaining level of care is important to minimize the adverse events during transfer. Patients had higher rates of adverse events if they were transferred during night shifts and on inotropic/vasopressor support