Aflatoxin B1 (AFB1) is a highly toxic metabolite of Aspegillus fungi that can contaminate animal feed. Cows that consume AFB1-contaminated feed excrete aflatoxin M1 (AFM1) in their milk. The aim of this study was to detect and quantify the amount of AFM1 in raw cow's milk and AFB1 in dairy feed samples in the Greater Addis Ababa milk shed using a value chain approach.