Strains of Aspergillus flavus that produce high concentrations of aflatoxin in cultures incubated at room temperature also produced these toxins in significant concentrations under conditions simulating household refrigeration (7.5° to 10 °C). The rate of toxin production at 10 °C was markedly influenced by preincubating cultures at room temperature for 24 hours. Solid cultures yielded higher concentrations of toxin than liquid cultures under the prevailing experimental conditions.