Acacia mangium is an exotic species that has been planted for afforestation in order to provide wood for domestic uses and for export. It is susceptible to pink disease caused by Corticium salmonicolor, wilt disease caused by Ceratocystis sp. and anthracnose disease caused by Colletotrichum gloeosporioides. These are major pathogens for A mangium in Thua Thien - Hue province and many other locations In Vietnam. Surveillance of antifungal compounds in A mangium has potential for the initial screening for disease resistance. Therefore, phyllode samples were collected from one tree showing good growth perfonnance in each of 42 families in a field trial established in 2009 in Thua Thien - Hue province. Leaf extracts were produced using MeOH and CH2Cl2 as solvents. Thirty five families showed high (40 - 60 percent suppression of diameter growth) or very high ( or = 60 percent) antifungal activities to Collectotrichum gloeosporioides, 30 families showed high or very high antifungal activities to Ceratocystis sp. and 37 families showed high or very high antifungal activities to Corticium saImonicolor. Overall, phyllode extracts of a total of 25 families (Hl, H3, H6, H7, H8, H9, Hl0, H11, Hl3, Hl5, Hl6, Hl7, Hl9, H20, H2l, H22, H25, H26, H27, H28, H29, H33, H36, H38 to H40) showing promising antifungal activity to the 3 pathogens tested.