The value of a systematic review or meta-analysis depends upon the care with which it is designed and conducted. A major factor in this is the literature search that identifies the articles to be reviewed. Careful selection of bibliographic databases and the use of well-designed search strategies based on the controlled vocabularies contained in published thesauri are essential to ensure retrieval of all relevant articles. This commentary offers suggestions for identifying the literature to be searched, designing a suitable search strategy, using a controlled vocabulary, and describing the bibliographic methodology underlying a systematic review or meta-analysis.