Background: Maintaining normothermia is essential during liver transplant. Serious adverse outcomes from perioperative hypothermia are well documented. Objective: To evaluate the core temperature changes during graft warm ischemia and reperfusion periods in adult and pediatric cases. Method: 30  recipients,(adult n=15  and  pediatric n=15)  were  enrolled  in this  study. Nasopharyngeal core temperature (NC'I) was recorded at the following points: 5 and 30 minutes after induction of anesthesia (tempi&2), the lowest NCT during dissection phase (temp3), the lowest NCT during the anhepatic phase and before implantation  of the graft (temp4), lowest NCT during warm  ischemia  (putting  the graft  at its bed till reperfusion)  (temp5),  also at 5 (temp6)  and 30 minutes  (temp7) after reperfusion, then before the end of surgery  (temp8). Results: Significant decrease in core temperature during the anhepatic phase (temp4), warm ischemia time (temp5), 5 minutes  after reperfusion  (temp6) and 30 minutes  after reperfusion (temp7)  with  mean  values  of  36.4  ± 0.47°C,  35.4±0.45°C, 35.2±0.50°C and  35.2±0.52°C respectively in the pediatric group, while in adult group the mean values36.3±0.330C, 36.1±0.380C, 36.1±0.6JOC and 35.9±0.34°C respectively. Conclusion:  Significant drop in NCT was observed at the beginning  of the warm ischemia period  that persisted  through  the reperfusion phase in both  adult and pediatric  recipients. Children  with a body  weight  <14 kg had their core temperatures affected  more  than adult patients  because  of   receiving  relatively  large  grafts  with   a  greater  GRWR.