Two corn hybrids, one resistant (FR35 ¥ FR20) the other susceptible (DF20 ¥ DF12) to storage fungi, were harvested and hand-shelled at 22% moisture, wet basis, and stored at this moisture in aerated l-kg bin units. Four Rovral® fungicide treatments plus an untreated control were tested using carbon dioxide evolution as the index of grain-deterioration rate. Equations of carbon dioxide weight versus time were fitted. The resistant corn hybrid manifested a lower deterioration rate than did the susceptible hybrid. Samples treated with fungicide showed a reduction in grain-deterioration rate compared with untreated samples.