Groundnuts are an important crop for Ugandan smallholders because they are high in protein, resupply nutrients to the soil, and are a storable source of wealth once dried. Adoption of virus-resistant seeds that increase yield and reduce yield variance may improve household food security, but the complex relationship is an empirical question. This article considers the effect of improved groundnut seed on smallholder food security in eastern Uganda. Results indicate that adopters have significantly higher household food security after controlling for observed and unobserved household heterogeneity. The food consumption score index increases more than 15 points with improved seed adoption.