Anatoxins are carcinogenic and extremely toxic secondary metabolites produced primarily by two fungi, Aspergillus flavus Link ex Fries and A. parasiticus Speare. Elimination of aflatoxin contamination in peanut (Arachis hypogaea L.) is a high priority of the peanut industry. Resistant cultivars should be an effective and low-cost part of an integrated aflatoxin management program. To date, no cultivated peanut has been reported with stable high levels of resistance to aflatoxin production. Arachis species and interspecific tetraploid lines have been evaluated for resistance to several peanut diseases and insect pests, and highly resistant accessions have been reported. Seven accessions of A. cardenasii Krapov. and W.C. Gregory, 29 of A. duranensis Krapov. and W.C. Gregory, and 17 interspecific tetraploid lines derived from A. hypogaea × A. cardenasii were inoculated with A. flavus strain NRRL 3357 and analyzed for aflatoxin content after incubation. On average, A. duranensis and A. cardenasii accumulated significantly less aflatoxin than A. hypogaea checks. The mean difference between the two wild species was not significant. Arachis duranensis accessions PI 468319 (GKBSPSc 30073), PI 468200 (GKBSPSc 30064), and PI 262133 (GKP 10038 sl.); and A. cardenasii accessions PI 262141 (GKP 10017) and PI 475997 (KSSc 36018) had reduced levels of aflatoxin accumulation and should be valuable sources of resistance to aflatoxin contamination. Of the interspecific tetraploid lines, only GP-NC WS 2 supported aflatoxin production not significantly different from resistant parent A. cardenasii GKP 10017, and it appears to be a line with reduced capacity for aflatoxin accumulation.