Critical illness is often painful, both from the underlying source of illness, as well as necessary procedures performed for the monitoring and care of these patients. Pain is often under-recognized in the critically ill, especially among those who cannot self-report, so accurate assessment and management continue to be major consideration in their care. Pain management in the intensive care unit (ICU) is an evolving practice, with a focus on accurate and frequent pain assessment, and targeted pharmacologic and non-pharmacologic treatment methods to maximize analgesia and minimize sedation. In this review, we will evaluate several validated methods of pain assessment in the ICU and present management options. We will review the evidence-based recommendations put forth by the largest critical care societies and several high-quality studies related to both the in-hospital approach to pain, as well as the short- and long-term consequences of untreated pain in ICU patients. We conclude with future directions.