Objectives As time and cost constraints in the conduct of systematic reviews increase, the need to consider the use of existing systematic reviews also increases. We developed guidance on the integration of systematic reviews into new reviews. Methods A workgroup of methodologists from Evidence-based Practice Centers developed consensus-based recommendations. Discussions were informed by a literature scan and by interviews with organizations that conduct systematic reviews. Results Twelve recommendations were developed addressing selecting reviews, assessing risk of bias, qualitative and quantitative synthesis, and summarizing and assessing body of evidence. Conclusions We provide preliminary guidance for an efficient and unbiased approach to integrating existing systematic reviews with primary studies in a new review.