The antifungal activity of tomato (Solanum lycopersicum) leaf volatiles (TLV), which are industrial residues, was investigated against three types of plant pathogenic fungi of Botryotinis fuckeliana, Glomerella cingulata and Fusarium oxysporum f. sp. melonis. The growth of B. fuckeliana and G. cingulata was completely inhibited by TLV extract volumes corresponding to 12 and 17 g of tomato leaves, respectively. The inhibition rate of a TLV extract volume corresponding to 17 g of tomato leaves against F. oxysporum f. sp. melonis was approximately 55%. The antifungal activity of TLV was thus shown to vary according to the type of plant pathogenic fungi. These results suggest the presence of a defense response against plant pathogenic fungi in tomato plants and that TLV are efficacious as a biological control agent.