This study investigated how much pain and pain relief cardiac surgery patients experience in Intensive Care Units (ICUs), and the accuracy of their recall later, during hospital recovery. Thirty-nine patients completed the first interview in the ICU, and 31 of them answered recall questions later. The worst pain patients experienced in the ICU was moderately high, and patients reported 65% pain relief from analgesics administered. In general, patients' later recalled ICU pain was less severe and recalled pain relief from pain medications was greater than what they had reported when in the ICU. A substantial number of patients were unable to rate the effects of analgesics because they did not remember being mediated. One gender difference was noted: women recollected having a higher "worst pain" in ICU than men. Although recall of ICU pain is less than accurate, ICU cardiac surgical patients have episodes of substantial pain. Despite advances in pain management, patients report that pain relief is frequently incomplete and that they do not remember receiving analgesics. A more proactive approach to pain management by health care professionals, which includes informing patients when they are receiving analgesics, may help to improve pain relief in cardiac surgical patients.