This paper evaluates the existing evidence of how and to what extent capture fisheries and aquaculture contribute to food security and poverty reduction. In doing so the authors evaluate the quality and scientific rigor of that evidence, identify the key conclusions that emerge from the literature, and assess whether these conclusions are consistent across the sources. This paper therefore differs fundamentally from a conventional literature review in the sense that its aim is not simply to conduct a review and synthesis of the existing literature, but to actually assess the scientific quality and consistency of that literature, and, where it exists, the reasons for inconsistencies.