Objective: To describe search and rescue activity performed by the National Park Service (NPS) on Denali, the highest point in North America., Methods: A retrospective review was performed of all search and rescue (SAR) operations by the NPS from 1990 to 2008. Descriptive analysis was used to describe these cases as well as chi-square and logistic regression analysis to determine which mountaineers were more likely to require a rescue., Results: During the study period, 1.16% of all Denali climbers required NPS SAR response. The majority of medical cases (68.9%) were due to high altitude and cold injuries, and the majority of traumatic cases (76.2%) resulted from a fall. Mountaineers that attempt routes other than the standard West Buttress route are more likely to require rescue. Climbers are 3% more likely to require a rescue with each year of advancing age. Similarly, mountaineers from Asia are more likely to require a rescue (odds ratio = 4.1), although this trend has diminished in the past decade., Conclusions: Mountaineers and rescuers should educate themselves on the environmental, logistical, and medical origins of Denali rescues. Certain demographic groups on certain routes are more likely to require a rescue on Denali. Rescuers should be aware of these groups and have the knowledge and capabilities to care for the medical issues that are common on SAR responses., (Copyright (c) 2010 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.)