The rapid rise in supermarkets in developing countries over the last several decades resulted in radical transformations of food retail systems. In Cape Town, supermarket expansion has coincided with rapid urbanization and food insecurity. In this context, retail modernization has become a powerful market-driven process impacting food access for the poor. The introduction of formal food retail formats is viewed simultaneously as a driver of food accessibility and as a detriment to informal food economies established in lower income neighborhoods. Through a mixed-methods approach, this article assesses the spatial distribution of supermarkets within Cape Town and whether this geography of food retail combats or perpetuates food insecurity, particularly in lower income neighborhoods. Spatial analysis using geographic information systems at a city-wide scale is combined with a qualitative case study utilizing semi-structured interviews and observational analysis in the Philippi township in order to illuminate the limitations of supermarket expansion as a market-oriented alleviation strategy for food insecurity. While supermarkets have been successful in penetrating some low-income communities, they are often incompatible with the consumption strategies of the poorest households, revealing the significance of the informal economy in Cape Town and the limitations of a food desert approach toward understanding urban food security.