We define the researcher as being “evidence-based” if he/she systematically reviews what is already known before embarking on a new study. Not being evidence-based as researcher is unethical, unscientific and wasteful. In order to define and promote the concept of “Evidence-based research” (EBR) we have just published a statement in The BMJ describing the implications of EBR for researchers, funding agencies, journals and other key stakeholder groups. The paper’s main take-home messages are that a systematic review of relevant evidence can establish whether the proposed research is truly needed or not; inform the optimal study design; and help to put new results into the context of existing knowledge.