Stress cracking of two corn hybrids (White, SC-10 and Yellow, SC-162) dried at various temperatures (35, 50, 60, 75 and 100 o C) from 21.2% to 13% moisture content and tempered for 24hr at ambient temperature (22  1 o C with available relative humidity) were tested. A breakage tester (BT-drop tester) was manufactured and a single-grain breakage susceptibility of two corn hybrids at various grain temperatures and times after drying (0, 3 ,6 , 10, 20 and 30min) were evaluated. The results indicated that, the damage index significantly increased as the drying temperature increased for two corn hybrids except at 100 o C with SC-162, it was decreased. The SC-162 was more susceptible to cracking more than SC-10 hybrid especially at lower grain temperature. Also, the predicted models and observation showed that both hybrids were plastic and had minimal breakage susceptibility at high grain temperatures from 72 to 93 o C, while, decreasing grain temperature increased breakage exponentially. After drying at both 75 and 100 o C, the breakage of the two corn hybrids increased rapidly for the first 10min after drying and reached an asymptotic level after around 10min cooling after finishing drying at ambient temperature. At the same drying temperature (75 o C), the breakage susceptibility increased by 37.4% for SC-10 and by 51.5% for SC-162 with the average stress cracks (multiple and checked) kernels for two hybrids of about 20.2%.