Using a portable infusion pump, intravenous opioid patient-controlled analgesia (PCA) permits a patient to selfdeliver a small bolus of opioid to achieve prompt relief without over sedation. Use of PCA for pain management is increasing in hospitals, largely because it can provide equivalent or better analgesia than conventional nurse-administered opioid analgesia, and patients are more satisfied with its use. There is no decisive pharmacological or clinical argument for the choice of one opioid rather than another. Thus, morphine remains the most frequently used opioid in PCA. The adjunction of non-opioid drugs to morphine in the PCA reservoir is still very controversial. A new investigational PCA transdermal system using iontophoresis to deliver fentanyl seems to provide an adequate pain control with the advantages of needle-free, preprogrammed, self-contained device. Whatever drug or device used, the overall success of the PCA technique relies mainly on the expert supervision of nurses or anesthesiologists in an Acute Pain Service. Indeed, PCA is effective and significant only on the condition that there is careful preoperative patient education and strict postoperative monitoring. In addition, preoperative patient selection allows to exclude patients with evidence of cognitive dysfunction or physical disabilities, making the use of the patientcontrolled device impossible. Caution is required among patients with respiratory or renal insufficiency. In the future, the indispensable improvement in the management of postoperative pain should lead to a greater expansion of PCA. However, more pharmaco-economic evaluations will be needed on the cost-effectiveness issue.