Abstract: Different concentrations of the essential oils obtained from hydrodistillation of five meliaceous plants were screened in vitro for effectiveness in inhibiting the growth and aflatoxin production by Aspergillus parasiticus. All the essences reduced the yield of fungal mycelia as well as the quantity of aflatoxin B1 produced in liquid culture. However, percentage inhibition was linearly related to oil concentrations. Essences from Khaya grandifoliola C.DC was the most efficacious, irrespective of the concentration. This was followed in a decreasing order of magnitude by the essential oils of Pseudocedrela kotschyi Harms, Entandrophragma utile Linn., Trichilia heudilotii Planch and Lovoa trichiliodes Harms. The amounts of aflatoxin B1 isolated from broth (culture filtrate) extract were usually twice that of the mycelia extract.