Many of food products and agricultural crops are contaminated with mycotoxins. Aflatoxins are the secondary metabolites of certain fungi such as Aspergillus flavus which have the ability to be toxigenic, carcinogenic and mutagenic agents. Hence many chemical compounds have been used in feed to prevent the fungal growth and aflatoxin formation. Organic acids have been used to prevent the growth reproduction of harmful fungi and secreting of aflatoxins. The effect of eight organic acids as antifungal agents on the growth of four fungi were studied. Acetic acid (10%) showed the highest inhibition effect on A. flavus growth being 45.21% while tartaric acid (5%) and citric acid (5%) gave the lowest inhibition effect of 0.42%. Formic, acetic and propionic acids had the highest inhibition effect on A. flavus growth. All Different organic acids under present study reduced aflatoxin B₁ (AB₁) secretion. The highest inhibition (50%) was observed for Rhizopus nigricans in the presence of formic acid (10%)