White Patch Disease (WPD), also known as White Pox, is a coral disease common in the Caribbean. Recently, it was observed for the first time in the Karimunjawa Archipelago, Indonesia. The lethal disease is characterized by patchy necrosis found all over the coral colony. We screened and characterized 87 isolates derived from 9 species of healthy coral-associated bacteria for their anti-pathogenic activity against WPD. Forty-nine out of 87 strains inhibited the growth of Halomonas meridiana and Virgibacillus salarius, the WPD associated bacteria isolated from infected Acropora muricata coral. The antipathogenic activity was re-screened using the disc diffusion method. BMT4 and BAF4 isolates displayed the strongest antibacterial activity and thus studied further. Partial sequencing of 16S rDNA showed that BMT4 and BAF4 isolates have a strong relationship with Bacillus flexus strain