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The number of intervention studies designed to improve quality of care is increasing exponentially, making it difficult to access all available information on a given subject. Systematic reviews are tools that provide health professionals with comprehensive and objective information. This article describes the main phases of a systematic review: formulating the research question, search and selection of studies, data extraction and analysis, assessment of the methodological quality of studies, and synthesis of the results. Interventions designed to improve professional practices and organisation of care have specific characteristics that determine the methodology of systematic reviews. For example, the often substantial heterogeneity between populations, organisations, and intervention settings among studies must be taken into account, which makes meta-analysis more difficult. Knowledge on specific features of systematic reviews designed to improve quality of care is essential to ensure a good review of the literature, or to evaluate the level of evidence of published systematic reviews.