Children's rights to have their views heard in matters that affect their lives are now well established since the publication of the UN Convention treaty (1989). Children with cancer generally prefer to be involved in decision-making and consider it important that they have the opportunity to take part in decision-making concerning their health care, even in end-of-life decisions. There is considerable support for involving children in healthcare decision-making at a level commensurate with their experience, age and abilities. Thus healthcare professionals and parents need to know how they should involve children in decision-making and what interventions are most effective in promoting shared decision-making (SDM) for children with cancer. To examine the effects of SDM interventions on the process of SDM for children with cancer who are aged four to 18 years. We searched the following sources: Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library, Issue 9, 2012); PubMed (1946 to September 2012); EMBASE (1974 to September 2012); CINAHL (1982 to September 2012); PsycINFO (1806 to September 2012); BIOSIS (1980 to December 2009 - subscription ceased at that date); ERIC (1966 to September 2012); ProQuest Dissertations and Theses (1637 to September 2012); and Sociological Abstracts (1952 to September 2012). We searched for information about trials not registered in these resources, either published or unpublished, by searching the reference lists of relevant articles and review articles and the following conference proceedings (2005-2012):American Academy on Communication in Healthcare (AACH), European Society for Medical Oncology (ESMO), European Cancer Conference (ECCO), European Association for Communication in Healthcare (EACH), International Conference on Communication in Healthcare (ICCH), International Shared Decision Making Conference (ISDM 2005-2011 as held every two years), Annual Conference of the International Society for Paediatric Oncology (SIOP) and Annual Scientific Meeting of the Society for Medical Decision Making (SMDM).We searched the International Scientific and Technical Proceedings database (2005 to September 2012). We also searched Dissertation Abstracts (from 1980 to September 2012).We scanned the ISRCTN (International Standard Randomized Controlled Trial Number) register and the National Institute of Health (NIH) Register for ongoing trials at: www.controlled-trials.com and clinicaltrials.gov on the 1 October 2012. We contacted authors for further details. We also contacted experts in this field.We did not impose language restrictions. Randomised controlled trials (RCTs) of SDM interventions for children with cancer aged four to 18 years. The types of decisions included were: treatment, health care, and research participation decisions. The primary outcome was SDM as measured with any validated scale. Two review authors undertook the searches, and three review authors independently assessed the studies obtained. We contacted study authors for additional information. No studies met the inclusion criteria, and hence no analysis could be undertaken. No conclusions can be made on the effects of interventions to promote SDM for children with cancer aged four to 18 years. This review has highlighted the dearth of high-quality quantitative research on interventions to promote participation in SDM for children with cancer. There are many potential reasons for the lack of SDM intervention studies with children. Attitudes towards children's participation are slowly changing in society and such changes may take time to be translated or adopted in healthcare settings. The priority may be on developing interventions that promote children's participation in communication interactions since information-sharing is a prerequisite for SDM. Restricting this review to RCTs was a limitation and extending the review to non-randomised studies (NRS) may have produced more evidence. We plan to expand the types of studies in future updates. Clearly more research is needed.