Caesalpinia sappan L (Sappanwood) contains antibacterial compounds and antioxidants that inhibit the growth of microbes. This study aimed to investigatethe microbiological and physicochemical qualities of pasteurized milk supplemented with 0, 2, 4, 6 and 8% (w/v) sappan wood extract. Data were analyzed using a completely randomized design factorial followed by the Duncan's new multiple range test. Preliminary analysis showed that sappan wood extract contained 44.66 ± 0.09 mg/100g phenols, 0.18 ± 0.01 mg/100mg flavonoids, 46.42 ± 0.23 mg/100g tannins, and antioxidant activity at 85.82 ± 0.25%. The addition of sappan wood extract significantly increased the antioxidant activity (P < 0.05) of pasteurized milk during storage. Pasteurized milk supplemented with sappan wood extract had a lower total bacterial count (P < 0.05) than that of unsupplemented pasteurized milk, and supplemented milk showed strong antibacterial activities against Escherichia coli, Shigella flexneri, Salmonella thypimurium, Staphylococcus aureus, and Listeria monocytogenes.The addition of sappan wood slightly increased the protein content but did not affect pH, and viscosity. It is concluded that the addition of sappan wood extract increased the microbiological quality and maintained the physicochemical quality of pasteurized milk, thus extending the product's shelf-life. © All Rights Reserved.