We investigated the evidence base of Clinical Practice Guidelines (CPGs) on 10 major cancers from mainland China, the Hong Kong Special Administrative Region and Taiwan. We sought information about the delays between publication of the CPGs and their respective references, the geographical origins of the research reported in these references and the sources of funding for this research. We identified 396 CPGs from China, 42 from Hong Kong and 54 from Taiwan for ten major cancers, and 12,556, 3,652, and 4,485 references to these CPGs in the three territories, respectively. We determined the countries of the authors (for the non-Chinese references) and the Chinese provinces or cities (for the references in Chinese) and also analysed the funding sources for the research. Some 22% of the references cited in the CPGs from China were in Chinese, and some of their references were based on Traditional Chinese Medicine (TCM), particularly in mainland China and for gastrointestinal cancers. The references in the Chinese CPGs tended to cite Chinese research less than expected, but Japanese research rather more – as did the references in the Hong Kong and Taiwanese CPGs, which over-cited research from their own territories. The sources of financial support for the international references were mainly public grant-giving bodies and pharmaceutical companies from the USA, Japan and Europe, rather than the main Chinese governmental funders. The rapidly increasing Chinese cancer research output will make the latter funding sources more important in future, and they may also be expected to influence the evidence base of the Hong Kong and Taiwanese CPGs. However, since Chinese cancer research is very basic (rather than clinical), its direct influence on cancer care is likely to be less than might be expected.