Paediatric pain management has made great strides in the past few decades in the understanding of developmental neurobiology, developmental pharmacology, the use of analgesics in children, the use of regional techniques in children, and of the psychological needs of children in pain. The consequences of a painful experience on the young nervous system are so significant that long-term effects can occur, resulting in behavioural changes and a lowered pain threshold for months after a painful event. Accurate assessment of pain in different age groups and the effective treatment of postoperative pain are constantly being refined, with newer drugs being used alone and in combination with other drugs, and continue to be explored. Systemic opioids, paracetamol, non-steroidal anti-inflammatories, and regional anaesthesia alone or combined with additives are currently used to provide effective postoperative analgesia. These modalities are often best utilized when combined as a multimodal approach to treat acute pain in the perioperative setting. The safe and effective management of pain in children includes the prevention, recognition, and assessment of pain; early and individualized treatment; and evaluation of the efficacy of treatment. This chapter discusses selected topics in paediatric acute pain management, with more specific emphasis placed on pharmacology and regional anaesthesia in the treatment of acute postoperative pain management.