Paenibacillus lentimorbus strain WJ5, a soil isolate showed in vitro antagonistic activity against several fungal phytopathogens belonging to the ascomycetes, basidiomycetes and oomycetes. The antifungal metabolite was extracellular and could be extracted with n-butanol. Its production was initiated at the end of the exponential phase, reaching a maximum after 5 days incubation at 30°C. Crude extract of the antifungal metabolite was thermostable (121°C for 3 h) and no loss of activity was recorded when exposed to proteinase K, sodium dodecyl sulphate (1%), Tween-80 (1%) and glycerol (1%). However, cationic hexadecyltrimethylammonium bromide and lysozyme inactivated the metabolite. The antifungal metabolite was purified by silica gel thin layer chromatography and Sephadex LH-20 size exclusion chromatography. Loss of activity during acid hydrolysis indicated the peptide nature of the antifungal metabolite. The FT-IR spectrum of the antifungal metabolite confirmed the presence of the peptide and glycosidic bonds.