Several Fusarium isolates known to produce zearalenone or T-2 toxin were tested for their toxigenic potential on heatsterilized whole and cracked soybeans, on soybean meal, and on rice. Moisture concentration levels and particle sizes of substrate were varied to determine effects on the amount and type of toxin produced. Only one of the three Fusarium isolates known to produce zearalenone, Fusarium roseum 'Graminearum', produced detectable amounts of this mycotoxin on soybeans. Fusarium sporotrichioides NRRL 3299, the T-2 toxin-producing isolate tested, produced T-2 toxin as well as T-2 tetraol, HT-2 toxin and neosolaniol on soybeans. HT-2 toxin production was greatly enhanced on soybean meal in comparison to rice cultures. These findings plus previous field observations suggest that soybean products present a mycotoxic hazard which warrants attention.