Banana and plantain whose fruits are a significant food source for the populations of Côte d’Ivoire, are sensitive to many diseases. Among them, the most significant due to the fungi is the black leaf streak disease caused by Mycosphaerella fijiensis which can involve more than 50 % of the losses of the production. The fight against this disease is primarily directed towards the use of synthetic fungicides. These substances, constitute a source of environmental pollution and foodstuffs rejection on the world market due to their residues. The biological fight using essential oils extracted from aromatic plants against this disease seems to be an alternative way. The present study was led in vitro to determine the antifongic activity of two essential oils extracted from Eucalyptus torelliana and Monodora myristica compared to a synthetic fungicide (spiroxamine), on the mycelial growth of Mycosphaerella fijiensis isolated from banana leaves in Côte d'Ivoire. Five concentrations of both essential oils and synthetic fungicide were added to the fungus culture medium (PDA). The mycelial growth was measured every 3 days during 21 days in the Petri dishes. The essential oil extracted from Monodora myristica presented a high fongitoxic effect at concentrations uper 7 000 ppm with a CI50 equal to 744.046 ppm. On the other hand the essential oil of Eucalyptus torelliana and synthetic fungicide had an increasing fongitoxic activity according to concentrations used. Their CI50 were respectively 3158.900 and 0.0145 ppm. Essential oils from the flora of Côte d’Ivoire can reduce or inhibit the mycelial growth of Mycosphaerella fijiensis and can constitute a means of effective biological fight against the black leaf streak disease.disease.">