This study was designed to observe the effects of temperature cycling on the aflatoxin production by Aspergillus parasiticus R-716 in modified SLS medium. Temperature cycling resulted in total aflatoxin production more than did constant incubation at either 28℃, which was considered to be optimum for aflatoxin production, or 17.5℃, which had the same total thermal input as the temperature cycling. The aflatoxin biosynthesis correlated with the color intensity of media, but was controversal with lipid biosynthesis, and aflatoxin concentration is nut related to changes in the fatty acid compositions of used strain.