The management of pain in the patient with advanced cancer requires comprehensive assessment and expertise in the application of many therapeutic techniques. Given the complexity of the problems posed by these patients, it is not surprising that most aspects of palliative care derive from personal anecdote and clinical consensus, rather than well-defined guidelines based on research findings. In the absence of such guidelines, unresolved issues and controversies abound. This review discusses some of the most important of these topics, which range from the overall system of care and quality of assessment to the specifics of pharmacotherapy and other modalities of treatment. In so doing, the rationale for some of the accepted clinical approaches can be clarified, others that are as yet little known can be highlighted, and the issues most in need of further investigation can be defined.