There is very limited information regarding the effects of feed-borne ' Fusarium' mycotoxins on broiler breeders. Experiments were conducted, therefore, to investigate the effects of feeding grains naturally contaminated with 'Fusarium' mycotoxins on performance of broiler breeders. The efficacy of a polymeric glucomannan mycotoxin adsorbent (GMA) in preventing ' Fusarium' mycotoxicoses was also determined. These experiments demonstrated that feeding of grains naturally contaminated with 'Fusarium ' mycotoxins can affect performance of broiler breeders. Broiler breeders may have higher tolerance to 'Fusarium' mycotoxins compared to broilers or layers. It was concluded that blends of grains naturally contaminated with 'Fusarium' mycotoxins should be fed with caution to broiler breeders because of the possible adverse effects on performance and immune status.