Postoperative pain is a major health care issue. Several factors have contributed to inadequate postoperative pain control, including a lack of understanding of preemptive pain management strategies, mistaken beliefs and expectations of patients, inconsistencies in pain assessment practices, use of as-needed analgesics that patients must request, and lack of analgesic regimens that account for inter-individual differences and requirements. Untreated acute pain has the potential to produce acute neurohumoral changes, neuronal remodeling, and long-lasting psychological and emotional distress, and may lead to prolonged chronic pain states. To effectively manage postoperative pain, nurses must be able to adequately assess pain severity in diverse patient populations, understand how to monitor physiological changes associated with pain and its treatment, be prepared to address the psychosocial experiences accompanying pain, and know the consequences of inadequate analgesia. It is important for nurses to be aware of relevant research and evidence-based guidelines that are available to guide pain assessments and patient-monitoring practices.