Following a request from the European Commission to address the risks and benefits as regards fish/seafood consumption related to relevant beneficial substances (e.g. nutrients such as n-3 long-chain polyunsaturated fatty acids) and the contaminant methylmercury, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver a Scientific Opinion on health benefits of seafood consumption in relation to health risks associated with exposure to methylmercury. In the present Opinion, the NDA Panel has reviewed the role of seafood in European diets and evaluated the beneficial effects of seafood consumption in relation to health outcomes and population subgroups that have been identified by the FAO/WHO Joint Expert Consultation on the Risks and Benefits of Fish Consumption and/or the EFSA Panel on Contaminants in the context of a risk assessment related to the presence of mercury and methylmercury in food as relevant for the assessment. These included the effects of seafood consumption during pregnancy on functional outcomes of children's neurodevelopment and the effects of seafood consumption on cardiovascular disease risk in adults. The Panel concluded that consumption of about 1-2 servings of seafood per week and up to 3-4 servings per week during pregnancy has been associated with better functional outcomes of neurodevelopment in children compared to no consumption of seafood. Such amounts have also been associated with a lower risk of coronary heart disease mortality in adults and are compatible with current intakes and recommendations in most of the European countries considered. These associations refer to seafood per se andinclude beneficial and adverse effects of nutrients and non-nutrients (i.e. including contaminants such as methylmercury) contained in seafood. No additional benefits on neurodevelopmental outcomes and no benefit on coronary heart disease mortality risk might be expected at higher intakes.