Meta-analysis is a quantitative method to objectively synthesize the results from different studies on the same topic. Meta-analysis is considered as evidence for clinical care but also references for clinical de¬cision. The purposes of this article were to elaborate the definition of origins of meta-analysis, the current trends and category of meta-analysis, and the application of meta-analysis in nursing research. We hope that nurses gain understanding on the clinical importance of meta-analysis in nursing care.