Tomatoes (Solanum lycopersicum L.) is one of the main crops in Syria. Fusarium wilt disease caused by the fungus Fusarium oxysporum f. sp. lycoprsici (Fol) isolated from local production fields of Syria( Atma), is one of the most important diseases that affect tomato plants. This research aims to isolate the (Fol) of infected plants, And test Four fungicides in inhibiting the growth of mycelium of the fungus Fusarium oxysporum. (Fol) in the laboratory, And det ermine the best fungicide and the best concentration in inhibiting the growth of the fungus colony. The fungicide Bavastin was the best among the fungicides and inhibited the growth of the (Fol) fungal colony by 76.71%. with significant differences with the fungicides (Thiophanat, Proficor, and Fosetyl aluminum) whose inhibition rates were (63.29%, 57.53%, and 60.82%) respectively. Without significant differences, it was found that the use of low concentrations of fungicides was less effective in inhibiting the growth of the fungal colony.