. Djatnika, I 2012. Selection of Antagonistic Bacteria for Controlling of Fusarium Wilt on Phalaenopsis Plants. Fusarium wilt is an important disease as constraint on production of orchid plants. The control of Fusarium wilt of orchids with fungicides often use by farmers. Orchid plants are often displayed as a decoration which is close to the human environment, so the application of pesticides have to get attention. It is therefore necessary to find another method that is safe for environments, such as using of biological control. The purpose of the study was to get isolates of bacterial antagonists for controlling of Fusarium wilt of Phalaenopsis plants. The experiment was conducted at Laboratory and Screenhouse of Indonesian Ornamental Plant Research Institute, Segunung (1100 m asl.) and the microbes were isolated from horticultural area in West Java and DKI Jakarta since January until December 2010. The research comprised of isolation of Fusarium spp. from orchid plants in some location, isolation of bacterial antagonists, the effectiveness of the bacteria to suppress Fusarium spp. growth in laboratory, and the effectiveness of the bacteria to control Fusarium wilt on Phalaenopsis plants in the screenhouse. The results showed that the causal Fusarium wilt of Phalaenopsis plants was identified as Fusarium oxysporum. Three of 154 isolates of bacteria, i.e. isolates number of B23, B26, and B37, could suppress of F. oxysporum growth on PDA media. Observation up to 10 weeks after inoculation, the three bacteria could reduce the number of plants attacked by Fusarium wilt , which were 46.9; 48.9; and 65.3% respectively, and each of them suppress wilt disease intensity 50.5, 43.9, and 55.1% respectively.