[Objective] This study was conducted to investigate the effects of Penicillium spp. and Trichoderma spp. on the growth of Pleurotus ostreatus (oyster mushroom) and to screen effective disinfectants to control them and other pathogenic microbes. [Method] Six strains or species of Penicilliurn and Trichoderma were inocu- lated into PDA plates growing with P. ostreatus to observe the growth of their mycelia. And the inhibitory effects of hydrogen peroxide, bromogeramine bromide, 84 disinfectant, lysol, potassium permanganate, and 75% medical alcohol on Trichoderma pleuroticola, Trichoderma viride, Trichoderma harzianum, Penicillium citrinum, Penicillium thomii and Penicillium brevicompactum were detected. [Result] Confrontation test revealed that Penicillium spp. and Trichoderma spp. competed for nutrients with P. ostreatus mycelia, antagonized against the growth of P. ostreatus mycelia, invaded and twined around P. ostreatus mycelia, and also produced toxins poisoning P. ostreatus mycelia. The six disinfectants exhibited different inhibitory effects against different species of Penicillium and Trichoderma. Among them the in- hibitory effects of bromogeramine bromide against the six species of Penicillium and Trichoderma were significantly different. However, the inhibitory effects of 3% hydrogen peroxide, 84 disinfectant, 5% lysol, potassium permanganate and 75% medical alcohol were significantly different among Penicillium spp., but did not among Tri- choderma spp. [Conclusion] Bromogeramine bromide can be used to control the bacteria and fungi in mushroom production for it has significant inhibitory effects on the six species of both Penicillium and Trichoderma.