Abstract: Three biological fungicides, Biocont-T, Funga stop and Polyversum constituted, respectively by Trichoderma harzianum, natural extracts (mint oil and citric acid) and Pythium oligandrum, were tested against F. oxysporum f. sp. tuberosi causing potato vascular wilt. Funga stop proved to be the most effective in inhibiting by 72 to 76% the mycelial growth of this pathogen on PDA media after incubation for six days at 25 °C. Biocont-T also limited its development by 37 to 63%. However, Polyversum showed a very little activity in controlling this fungus in vitro. All bio-fungicides reduced disease incidence compared to the untreated control. Funga stop and Biocont-T were the most active during the bioassay. Whereas, Polyversum had a lesser effect in controlling this disease.