With an increasing focus on evidence-based practice in health care, it is important that nurses understand the principles underlying systematic reviews. Systematic reviews are used in healthcare to present a comprehensive, policy-neutral, transparent and reproducible synthesis of evidence. This article provides a practical overview of the process of undertaking systematic reviews, explaining the rationale for each stage. It provides guidance on the standard methods applicable to every systematic review: writing and registering a protocol; planning a review; searching and selecting studies; data collection; assessing the risk of bias; and interpreting results.