Development of acacia plantations, mainly Acacia mangium, in Sabah and Sarawak has progressed well for over three decades. Despite some disease problems, A. mangium is still the preferred plantation species in Sabah and Sarawak as it is a fast-growing and flexible species that is able to grow on poor and degraded soils. However, reports of widespread mortality of young plantations due to root-rot diseases and Ceratocystis wilt, particularly in Indonesia, and fear of future failure of acacia plantations have caused alarm among plantation managers and growers, leading some quarters to call for a change of tree species for fastgrowing plantations. This paper discusses two of the major diseases affecting Acacia species, particularly A. mangium, the successes and failures of acacia plantations in Sabah and Sarawak, and the way forward.