['This study was performed to examine the characteristics of indoor and outdoor falls in older patients and the factors related to severe injury in the emergency department (ED).', 'In total, 26,515 patients fell indoors and 19,581 outdoors. The general and clinical characteristics were compared between the two groups and factors associated with severe injury following the falls were evaluated.', 'Younger males fell more frequently outdoors than indoors. The common activities during outdoor falls were sports and leisure activities. Environmental hazards lead to more outdoor falls than indoor falls. Factors associated with severe injury after indoor falls were transport to the ED by public ambulance or from another medical facility rather than individual transportation, fall from stairs rather than fell over, and a head and neck injury rather than a lower extremity injury. Factors related to severe injury after outdoor falls were male sex, transport to the ED by public ambulance or from another medical facility or by another method rather than individual transportation, state employed, fall from stairs rather than fell over, head and neck or thorax or abdomen injury rather than a lower extremity injury.'] Does risk factors for severe injury following indoor and outdoor fall in geriatric patients?