SUMMARYA study was made of the occurrence ofGibberella zeaein 102 samples of wheat marketed in 1975. Of the 19 zearalenone-positive samples,G. zeaeinfection of surface-sterilized wheat kernels ranged from 6% to 60%. NoG. zeaewas detected in 35 samples. The highest level of zearalenone was 11,054 ppb in a sample with 36% infection. In wheat, 17 samples with over 10% infection were positive for zearalenone and seven were negative.Aspergillus flavuswas detected in 53 samples with an infection of 2–46% but no aflatoxin was found. Various species ofAlternarlawere found in 100 of the 102 samples.