Enteric methane from dairy cows is an important source of methane emissions and has been increasing more rapidly than emissions from beef production. Methods proposed to decrease enteric methane production by dairy cows include dietary modifications, use of feed additives, feed efficiency improvements, mechanical devices, but also selective breeding of low-methane-producing animals. Dietary modification and feed additives have practical advantages as methane reduction strategies, but lack of proven, commercially available and cost-effective additives remains a limiting factor. More generally, current information is limited about the costs and benefits of nutritional strategies for enteric methane reduction and until more research is available on-farm, the industry lacks practical knowledge of true effects or costs to the dairy producer. This research proposes a systematic evaluation of existing evidence regarding the potential costs and benefits (e.g., increased production and revenues) of nutritional strategies to reduce enteric methane. The systematic review will: a) Identify relevant literature on the range of proposed nutrition-focused interventions, assessing the type and nature of information on their economic costs and benefits; b) summarize the patterns of results with regard to economic costs and benefits of nutrition-focused interventions to reduce enteric methane; c) undertake a determination of factors affecting cost and benefit outcomes; d) propose a framework for inclusion of information on economic costs and benefits in studies of nutritional strategies to reduce enteric methane and relevant metrics (such as the cost per unit of methane reduction); and e) highlight promising nutrition-based approaches and discuss priority information needs for practical application.