Wang, Shih-Hao(1,2) Tai-Yi Hsu,(1,2) Jen-Tse Kuan,(1,2) Jih-Chang Chen,(1,2) Wei-Fong Kao,(3) Te-Fa Chiu,(1,2) Yu-Cheng Chen,(1,2) and Hang-Cheng Chen.(1,2) Medical problems requiring mountain rescues from 1985 to 2007 in Yu-Shan National Park, Taiwan. High Alt. Med Biol. 10:77-82, 2009.-Medical problems requiring mountain rescue in densely populated and low-latitude locations like Taiwan have rarely been studied or discussed. The purpose of this research was to examine mountain-rescue operations that occurred in Yu-Shan National Park Taiwan from 1985 to 2007. Of 186 mountain-rescue operations, 128 involved medical problems (illnesses or injuries). Of the medical problems, 62% involved trauma and 41% involved illness. Ninety-nine ground rescues, 14 helicopter rescues, 38 combination ground and helicopter rescues, and 20 rescues using unclear methods were conducted, and the remaining 15 rescue operations did not involve visitors. In the 186 rescue operations, 330 visitors were rescued, 240 of them survived, 66 were dead, and 24 had an unclear outcome. Factors that affected the type of injury or the probability of survival included the activity, altitude, composition of the visitor group, weather, and occurrence of natural disasters. Mountain-rescue operations in which both ground and helicopter rescue were utilized were more successful. Our retrospective findings indicate that wilderness emergency services should have the capability of performing rescues in rugged terrain and be flexible in their approach to any situation arising in mountainous regions; proper training of onboard helicopter medical personnel is also necessary. In conclusion, we recommend setting up a standard system for reporting mountain- rescue operations, with statistics compiled annually.