From research reports published over the last 20 years, it appears that moderate to severe uncontrolled pain may be the norm for hospitalized patients despite recent advances in the management of pain. Research on the extent of under-management of pain and the factors associated with it is examined and summarized in this paper. Methodological imperfections of the research are identified. Several explanations for pain under-management have been proposed and these are reported. A clinical decision making model is also reviewed and it is suggested that this model could be applied to pain management problems. Further, it is suggested that this model may be very useful in developing educational interventions to improve health practitioners' clinical skills in pain management.