Estimates suggest that a substantial volume of food intended for human consumption is lost or wasted globally, underlining the importance of reducing food waste to address environmental concerns. This study examines the generation and associated carbon footprint of 25 different food waste fractions from ten Brazilian street markets. The aim is to identify hotspots within food product categories, analyse the causes of food waste and investigate potential risk factors that hinder the reduction of food waste. This research seeks to provide support when deciding on prevention and valorisation measures, and waste management strategies to enhance the sustainability of the agrifood system. The study reveals that 4.98 kg and 20.15 kg of food per stall are wasted every week in street markets at Ribeirão Preto and São Paulo, respectively, resulting in an average carbon footprint of 6.74 kg and 35.20 kg CO2 eq. per stall. The three food product categories that have the largest carbon footprint are (1) unavoidable food waste, (2) leaves, flowers and stems, and (3) meat. The annual food waste generation in Ribeirão Preto and São Paulo street markets is estimated to be 0.50 and 2.22 kg per capita per year, respectively. This suggests that diverting organic food waste, particularly unavoidable waste, from landfills to other waste management methods holds significant potential for reducing the carbon footprint. Leaves, flowers and stems as well as meat should be prioritized for prevention measures.