The occurrence of aflatoxins in market betel nut samples was studied. It was observed that several betel nut samples were infested with aflatoxin‐producing fungus,Aspergillus flavus.Out of 32 samples collected from various places, 12 were positive for aflatoxin. Aflatoxin B1was detected in all the positive samples. Other aflatoxins were also detected in some samples. Boric acid, propionic acid and potassium metabisulphite were used for the control of aflatoxin B1on betel nuts. Propionic acid was most effective in inhibiting aflatoxin production on betel nut after intervals of 2 (62%) and 4 (85%) weeks. Controlling the occurrence of aflatoxin could safeguard the users from the health hazards of aflatoxins.