The present study investigated the role of intensive care units (ICU) during disasters, including the responses of our ICU following the Great East Japan Earthquake on March 11, 2011. Our ICU comprises 8 beds for postoperative inpatients and those with rapidly deteriorating conditions; 20 beds in an emergency unit for critically ill patients; and 17 beds for neonates. It is important to secure empty beds when a major disaster occurs, as was the case after the Great Hanshin Earthquake, due to the resulting large numbers of trauma patients. Therefore, each ICU section cooperated to ensure sufficient space for admissions following the Great East Japan Earthquake. However, unlike the Great Hanshin Earthquake, securing beds was ultimately unnecessary due to the nature of the recent disaster, which also consisted of a subsequent tsunami and nuclear accident. Therefore, air quality monitoring was required on this occasion due to the risk of environmental radioactive pollution from the nuclear disaster causing problems with artificial respiration management involving atmospheric air. The variability in damage arising during different disasters thus requires a flexible response from ICUs that handle seriously ill patients.