Aflatoxin contamination of agricultural commodities is of great concern for both public health and the economy in southeast Asian countries. Near the end of 1998, we collected twenty-six agricultural samples from three different markets in central and east Java and Bali in Indonesia and analysed for aflatoxins. Also, 22 Aspergillus flavus group isolates from these commodities and soil samples were tested for their mycotoxin productivity. Aflatoxin B1 was detected in five of eight peanut and four of five maize samples. No aflatoxins were detected from six rice, three soybean, or four other bean samples. The highest amount of aflatoxin B1 detected was close to 6 ppm in one peanut sample followed by 300 ppb in one maize sample. Aflatoxin G1 and G2 were not detected in any of the samples. Seven out of 22 Aspergillus f lavus group isolates produced detectable amounts of aflatoxin B1 and B2 in liquid culture medium (0.18 to 21 ppm of aflatoxin B1 and 0.002 to 0.8 ppm of aflatoxin B2), but none produced detectable amounts of aflatoxin G1 or G2. A11 22 isolates produced kojic acid (0.07 to 3.18%) and 21 produced cyclopiazonic acid (trace to 54 ppm)•