introduction Moderate to severe pain in cancer is common and affects 70-80% of patients with advanced disease. We have the means and the knowledge to relieve most pain in cancer for most patients, but evidence from surveys and observational studies shows that many patients have troublesome or severe pain and do not get adequate relief The skilled use of opioid analgesics is crucial to the relief of cancer pain, but there is a shocking lack of evidence to support clinical practice. The so-called analgesic ladder is the central idea of the WHO 1996 guidelines on cancer pain relief, in which the choice of analgesic is determined by the severity of the pain. The WHO method has been adopted worldwide but the lack of up-to-date evidence knowledge. and opioid availability have obstructed the path to effective relief of cancer pain Random controlled trials (RCTs) in patients with cancer pa are beset by difficulties,' In the absence of hard evidence from RCT's, expert consensus and clinical guidelines might be helpful, because cancer pain relief is a specialist area but most care is delivered by non- practitioners. The European Association for specialist Palliative Care (EAPO) research network published its first guidelines on the use of morphine and alterna opioids in cancer pain in 1996, and published an update in 2001' In this Review we present further work done to strengthen the scope of the EAPC recom mendations by the application of rigorous, evidence based methodology