In view of the warmth and hunidity in Korea, there is little possibility to avoid the fungal contamination of rice soybean paste which are major foodstuffs in this country. In order to isolate aflatoxin producing fungi from these foodstuffs, 6 samples of rice were collected from the farmhouses at Cbangsung and 40 samples of soybean paste in Seoul areas. The peptone glucose chloramphenicol, Czapek-Dox agar and malt agar were used for the isolation and identification of fungi, and Adye and Meteles medium and/or Sahouraud medium for the production of toxins. The cultures for the toxin production were done at $25^{circ}C$ for $5{sim}7$ days. Eleven Penicillium species were isolated. from 6 samples of rice, and 37 Aspergillus flavus, 48 Aspergillus species, 1 Penicillium species and 105 others were isolated from 40 samples of soybean paste. Among these, one Penicillium species isolated from rice was found to be aflatoxin producing strain, and the toxin was quantitatively measured. Aflatoxin appeared to be more favorably produced in the glucose Sabouraud medium than in the Adye and Meteles medium.