A nuclear war using less than 1% of the current global nuclear arsenal could produce climate change unprecedented in recorded human history and large impacts on agricultural productivity. These e↵ects would be most severe for the first five years after the nuclear war and may last for more than a decade. This paper calculates how the price and availability of food worldwide would change by employing the Environmental Impact and Sustainability Applied General Equilibrium model. It evaluates how results depend on assumptions about how free trade would continue in a post-war economic environment. The results suggest that preserving the world trading system is key to preventing widespread food shortages as a thriving world trading system minimizes the costs born from disruptions to climate. The analysis shows that the regional nuclear war scenario would a↵ect regional food supply systems, especially in high latitude regions. Although the global average impact on wheat is only a few percentage points, the regional nuclear war leads wheat production in EU 28 countries to plumed, on average, by more than 15%. The model also suggests that regional impacts may result in a plausible domino e↵ect with substantial negative ramifications for local food supplies.