Abstract: In the present study the antimicrobial activity of essential oils of allium bulb (Allium cepa L.), black cumin seeds (Nigella sativa L.) and eucalyptus (Eucalyptus globulus Labill) were evaluated against five fungi (Fusarium oxysporum f.sp. melonis, Fusarium solani, Fusarium verticillioides, Sclerotinia sclerotiorum and Rhizoctonia solani). Allium cepa oils completely inhibited the mycelial growth of Fusarium oxysporum f.sp. melonis, Fusarium solani and Sclerotinia sclerotiorum at 500 ppm concentration. While, E. globulus oil completely inhibited the radial growth of F. solani, S. sclerotiorum R. solani. On the other hand, the percentage inhibition varied in case of Nigella sativa oil is 28.6-73.9% from (F. oxysporum f.sp. melonis, F. verticillioides) at 500 ppm concentration. Whereas, the spore germination of F. oxysporum f.sp. melonis and F. solani were completely inhibited by the application of A. cepa oil, while the oil of eucalyptus completely inhibited the spore germination of F. solani and highly effective against spore germination of F. oxysporum f.sp. melonis, F. verticillioides with 98 and 93%, respectively at 500 ppm concentration. Considering the inhibition in the growth and spore germination, it concluded that allium and eucalyptus essential oils could be used as possible bio-fungicides alternative to synthetic fungicides against phytopathogenic fungi.