Trichoderma species are known as excellent biocontrol agents against soil-borne pathogens that cause considerable crop losses. Among them, Verticillium dahliae Kleb is the causative agent of Verticillium wilt. In this study, the ability of Trichoderma strains to antagonize V. dahliae was evaluated. In vitro dual culture tests were conducted in a completely randomized design using 53 Trichoderma isolates, collected from different locations in Algeria. Among these, only 15 of significantly inhibited the mycelial growth of 2 isolates of V. dahliae. Antagonist isolates of Trichoderma were characterized through phenotypic and molecular means. The isolates were divided into three groups: T. harzianum, T. longibrachiatum and T. artoviride. The results revealed that T. artoviride (T2) exhibited the highest antagonistic ability against V. dahliae (V1 and V2) with inhibition percentage of 74.41% and 69.50%, respectively. T. harzianum (T4) exhibited the lowest antagonism against V2 (41.07%). Trichoderma isolates showed a very high activity in both bioassay distance culture and antibiotic assay. The three Trichoderma strains (T2, T7 and T10) successfully controlled Verticillium wilt on tomato with disease reduction of 95.98%, 90.71% and 92.98%, respectively.