There has been a substantially increased interest in biomedical research impact assessment over the past 5 years. This can be studied by a number of methods, but its influence on clinical guidelines must rank as one of the most important. In cancer, there are 43 UK guidelines (and associated Health Technology Assessments) published (up to October 2006) across three series, each of which has an evidence base in the form of references, many of which are papers in peer-reviewed journals. These have all been identified and analysed to determine their geographical provenance and type of research, in comparison with overall oncology research published in the peak years of guideline references (1999-2001). The UK papers were cited nearly three times as frequently as would have been expected from their presence in world oncology research (6.5%). Within the United Kingdom, Edinburgh and Glasgow stood out for their unexpectedly high contributions to the guidelines' scientific base. The cited papers from the United Kingdom acknowledged much more explicit funding from all sectors than did the UK cancer research papers at the same research level.