ObjectiveTo describe the philosophy and approach to patient care called evidence based medicine, and to highlight how it can enhance the practice of intensive care.Data SourcesWe searched MEDLINE, reference lists, and our personal files to identify relevant literature.Study SelectionArticles on intensive care practice, critical appraisal, clinical research, and healthcare delivery were selected for discussion.Data SynthesisWe summarize the rationale for evidence based medicine, its applications and future developments, and suggest several methods for intensivists to use evidence based medicine in their practice and teaching.ConclusionsEvidence based medicine can complement other foundation disciplines in intensive care. This is the first article in a series entitled ``Evidence Based Critical Care Medicine'' which will demonstrate how this approach can be used at the bedside.(Crit Care Med 1996; 24:334-337)