This study evaluated lipid oxidation in refrigerated (±4ºC) duck meatballs treated with novel antioxidants over 21 days of storage. The duck meatballs were treated with a control substance, Cosmos caudatus (ulam raja) or Polygonum minus (kesum) extract, or BHT (butylated hydroxytoluene), and data was collected every three days. These results showed that Cosmos caudatus and Polygonum minus had better antioxidant effects on duck meatballs than BHT or the control. Folding and microbial potency test results were not significantly different among the three antioxidants tested but were better in antioxidant-treated samples than in control samples. However, Cosmos caudatus and Polygonum minus were slightly more effective in preventing microbial growth. This result suggests that Cosmos caudatus and Polygonum minus may be potentially useful natural resources for enhancing the shelf life of duck meatballs.