This Introduction summarises some of the key research findings of the papers in this special issue of The World Economy drawn from a European Commission co-funded project on non-tariff measures (NTMs) affecting agri-food trade of the EU and its trade partners. The project created a large symmetric international database of regulations and standards, constructed measures of their heterogeneity and evaluated the effects of heterogeneity on trade. Cases studies for selected dairy, meat, and fruit and vegetable products complement the aggregate analysis. The findings suggest that at least for some import standards, the harmonisation of regulations will increase trade. Additional findings address the potential protectionist leaning of some NTMs, their welfare impact, third-country consequences of their imposition, interface of NTMs with tariffs and other border measures, negotiation strategies, North-South dimensions of NTM impacts and the value added from the application of diverse and novel models to the assessment of their effects.