Essential oil from Chamaecyparis obtusa leaves and water extract from Pseudotsuga menziesii sawdust were examined for antifungal activity against Trichoderma spp. (Trichoderma aggressivum, Trichoderma atroviride, Trichoderm harzianum. Trichoderma koningii, Trichoder-ma viride). Generally, essential oil and water extract inhibited the growth of Trichoderma spp. by about 25% and 33%, respectively, at 1000 ppm. Antifungal activity of water extract was slightly higher than essential oil at 1000 ppm. Antifungal activity was increased with increasing concentration of essential oil and water extract. This study was carried out the investigation of the chemical composition of essential oil from Chamaecyparis obtusa leaves and water extract from Pseudotsuga menziesii sawdust. The essential oil was analyzed by GC-MS and water extract analyzed by GC-MS/HS. Thirty-eight components were identified, of which terpinyl acetate (13.41%), elemol (11.86%) and isobornyl acetate (7.89%) were the main compounds in essential oil. Twenty-four components were identified, of which 2-Isopropoxy-ethylamine (46.45%), Epifluorohydrin (8.62%) and Trans-2,3-Dimethyloxirane (7.78%) were the main compounds in water extract. Based on all results described above, we conclude that the essential oil and water extact may have a potent in vitro antifungal activity against Trichoderma spp.