Background: Public health initiatives are often complex and pose particular challenges for researchers engaged in both their evaluation and the subsequent systematic review of such evaluations. Typically, such reviewswill include information from non-randomised quantitative and qualitative research for which a number of methods have been proposed, but no gold standard has emerged. Objectives: This presentation will use examples from a number of recent reviews around diverse topics, including preventing cardiovascular disease and skin cancer, to illustrate the potential and pitfalls of some current approaches, including around identifying relevant studies, quality appraisal, methods of analysis and synthesis, and how reviews of quantitative and qualitative research may inform each other. These examples are taken from the author’s work for the UK’s Centre for Public Health Excellence at the National Institute for Health and Clinical Excellence. Methods: Systematic reviews of qualitative and quantitative research to evaluate public health interventions using formal methods of narrative synthesis and meta-ethnography. Results: Undertaking systematic reviews to address policy makers’ public health questions offers one way of ensuring a rigorous approach to gathering and considering evidence is used. Expanding what is considered valid as evidence to include alternative study designs offers the possibility to help, for example, explain discordant quantitative findings or illuminate potential difficulties in terms of implementation and acceptance. Conclusions: While much progress has been made towards developing robust and valid methods for the review and synthesis for non RCT data, many uncertainties remain including: how to frame questions so that the most pertinent qualitative, as well as quantitative, research can be considered, how to weight contradictory findings from different study designs, what a synthesis of mixed evidence might look like and how to assess the quality of qualitative research.