The main focus of evidence-based practice is to identify more clearly those healthcare interventions that can be proved to be effective on scientific grounds, from the results of research studies and surveys that are undertaken for the purpose. Evidence-based practice has become a cornerstone for the United Kingdom’s health policy and is currently being examined and implemented throughout the British National Health Service (NHS). According to Elkan et al (2000), the main goal is to use research evidence for rationing scarce health care resources and finding feasible solutions to physiotherapy treatment challenges. Only those interventions that could be shown to be effective on the basis of scientific research and evidence would be priority candidates for NHS funding.This paper proposes to examine the principles of evidence-based practice in physiotherapy and to critically discuss whether evidence is the foundation on which the professional should justify his or her practice. Further, the part played by clinical experience, patient preferences, political agenda/ targets, and guidelines of the National Institute of Clinical Excellence (NICE) and National Service Framework (NSF) for health will be included in the discussion.The requirement for evidence-based practice applies to the entire physiotherapy profession and includes “managers, researchers, educators, and students as well as clinicians” (Morris 2003:231). Evidence-based practice requires sound professional judgment as well as sound clinical reasoning. The reasoning is needed to evaluate the quality of evidence, to apply that evidence, “and to manage those patients whose unique clinical presentations fall outside the population characteristics where evidence does exist, known as the grey zones of practice” (Jones et al 2006: 2). It is essential that physiotherapists should demonstrate the efficacy of their interventions. The most recognized method is to use critically appraised tools (CATs) which are procedures that are confirmed to be effective from research evidence, to guide the practice of physiotherapists and other healthcare professionals.