Transplantation is the only way to rescue the patients who are at end stage of kidney disease, liver disease, heart disease, lung disease and pancreas disease. Since the only source to access the suitable organ for transplantation is using of heomograft, we have decided to study brain death reasons in the cadavers which we transplanted their kidney, liver, heart, lung and pancreas to other patients. We studied 86 organ donor cadavers (kidney, Heart, Liver, cornea) who had admitted in ICU of Imam Reza hospital. Then reasons of admission and kinds of head injury were evaluated. We studied 86 brain death patients including 20 female (33/3%) and 66 male (76/7%). Reasons for admition are divided to 4 groups: 9 brain tumor, 68 head trauma (crashing, fall out of height, stricke ground), 6 cerebral hemorhage without trauma (such as aneurysm and brain stroke) and 3 cases of cerebral hypoxemia (suffocation, apnea after epilepsy). We found that head trauma specially caused by crashing is the most common reason for brain death. It is more common in men and in the age range of 10-30 years.