Adequate pain relief during the postoperative period has long been recognized as difficult to accomplish. The reasons for this are mentioned in a brief review of methods of pain control, and an overview of the detrimental effects of acute pain is given. This retrospective analysis of data from 36 patients set out to examine whether those whose night-time sleep was found to be disturbed by pain were subject to different patterns of analgesic provision from those whose sleep was not. Although no such differences emerged, it was found that analgesics were given approximately half as frequently during the night when compared with during the day. It was also noted that only 30-35% of the maximum doses of analgesics prescribed were actually given within the immediate postoperative period. The possible reasons for these findings are discussed.