Recently, phytopathogenic problems have been increasing day by day in cereal production and have adverse effects on its production. One of the most common methods applied to control phytopathogens is the use of synthetic chemicals. The impacts of pesticides on the environment and food safety have made their use controversial. Therefore, developing and applying methods that can replace agricultural chemicals is an issue that needs to be emphasized. In this sense, biocontrol can be an alternative approach against agrochemicals in terms of sustainable agriculture. In the present study, it was aimed to examine the biocontrol efficiency of Trichoderma harzianum against Fusarium graminearum, Fusarium culmorum and Fusarium avenaceum, causing product losses in wheat by dual culture tests and double plate assays. Results showed that T. harzianum had remarkable inhibition of mycelial growth of all Fusarium species in dual culture assays. Moreover, no statistically crucial differences were found in the double plate tests.