Two strains of Bacillus subtilis were isolated from the soil. Crude fungicides obtained from the culture broth of these strains grown aerobically in a medium containing chitin of marine waste displayed antifungal activity on pathogenic Fusarium oxysporum. B. subtilis W113 and B. subtilis W118 exhibited the maximal antifungal activity, when grown in a medium with the supplemented chitin being 1.75 and 0.75%, respectively. The inhibitory effects of the crude fungicides produced by these two strains were not significantly influenced by variation of pH. These crude fungicides were remarkably thermostable, and the inhibitory activities were retained to some extent even after the crude fungicides were heated at 100degreesC for 30 min. These characteristics were unique in comparison with other known bio-fungicides. The utilization of chitin of marine waste to produce chitinolytic enzymes/fungicides by B. subtilis is seen for the first time