The purpose of this study was to describe various dimensions of the pain experiences of intensive care unit (ICU) patients. A purposive, primarily surgical sample of 24 ICU patients from two hospitals was interviewed after transfer from ICU. All but one patient remembered their ICU stay. Although this and six other patients had no recall of pain, 63% of the sample rated their pain as being moderate to severe in intensity. In a subgroup of nine patients having cardiac surgery, mean morphine sulfate administration during the first three postoperative days was 14 mg/day. This group of patients reported a lack of total pain relief from analgesics. Patients also described various sources of their pain, difficulties they had in communicating their pain, and nonpharmacologic methods that helped relieve their pain. Results of this study clearly indicate that not only pain but its communication and treatment were significant problems for a substantial portion of this ICU sample. Further descriptive and experimental research of pain characteristics and treatment practices for ICU patients is urgently needed. Improvements in nursing practice that result from such research may make a substantial difference in the comfort and well-being of critically ill patients.