Cancer Research UK has recently sponsored a meeting, organized by the UK Medical Research Council, on cancer drug resistance. Several of the molecular mechanisms responsible for this clinical outcome, such as DNA interstrand crosslink repair, apoptosis evasion, cytochrome P450 and P-glycoprotein, were discussed. There was a special focus on leukaemia, breast and ovarian cancer, and the potential use of positron-emission tomography to study anticancer-drug resistance. The progress made in translating these findings to the clinic, like Gefitinib, P-glycoprotein phenotyping, or genome-wide analysis technology, was also discussed.