Although numerous clinical practice guidelines for pain management have been published throughout the last 12 years, inadequate pain relief remains a significant health care issue. Several patient-controlled analgesia (PCA) modalities are currently available for the treatment of acute postoperative pain, including intravenous (IV) PCA, epidural (PCEA), and oral PCA. Although PCEA and IV PCA are both commonly used modalities, IV PCA is considered the standard of care for postoperative pain management. Limitations of this modality do exist, however. Consequently, noninvasive PCA systems are under development to circumvent many of these limitations, including the fentanyl hydrochloride patient-controlled transdermal system (PCTS); (IONSYS Ortho-McNeil Pharmaceutical, Raritan, NJ) and a number of patient-controlled intranasal analgesia (PCINA) delivery systems. The objective of this article is to review the PCA modalities currently in use and to discuss those in development for the treatment of acute postoperative pain.