Pain in patients who are critically ill remains undertreated despite decades of research, guideline development and distribution, and intense educational efforts. By nature of their complex medical conditions, these patients present unique challenges to the delivery of optimal pain treatment. Outdated clinical practices and faulty systems, such as a formulary that allows dangerous prescriptions, present additional obstacles. A multidisciplinary and patient-centered continuous quality improvement process is essential to identifying barriers and implementing evidence-based solutions to the problem of undertreated pain in hospital ICUs. This article addresses barriers common to the ICU setting and presents a number of structured approaches that have been shown to be successful in improving pain treatment in patients who are critically ill.