Background: An accurate preoperative estimate of the graft weight and remnant liver volume is vital to avoid small-for-size syndrome(SFSS) in the recipient and ensure donor safety after Living donor liver transplantation (LDLT). CT has been widely used as a method for the preoperative volumetric assessment of the liver transplantation.The graft size as measured from preoperative imaging which is often different from the actual weight of the liver graft as obtained by the donor hepatectomy. The difference between preoperative volumetry and Actual graft weight (AGW) was graded into minimal difference (≤15%) and big difference (>15%). Aim of The Work: This study was conducted to assess different preoperative factors that might affect the difference between estimated graft weight and actual graft weight in liver transplantation. Patients And Methods: This single center retrospective study was conducted on 86 cases who have been subjected to donation for liver transplantation in Ain Shams Center of organ transplantation.Donors were divided into two groups: Group (A): formed of 33 donors who showed minimal difference (≤15 %) between  EGV and AGW. Group (B): formed of 53 donors who showed big difference (>15 %) between  EGV and AGW. Each donor data was examined for: Age, Sex: male or female, Body mass index (BMI), Lipid profile (positive / negative) Type of hepatectomy (Rt lobe / Lt lobe), AGW.Estimated graft weight (EGW), Total liver volume, Liver biopsy: Fibrosis (positive/ negative), Steatosis: Negative:  (0%) and Positive: (5% or 10%). Results: EGW of 903 gm was identified as cutoff point of the best specificity with the best sensitivity showing 60.4 % and 60.6% for sensitivity and specificity, respectively. At this cutoff point, 47.7% of cases (n=41) showed EGW < 903 gm, while 52.3% of cases (n=45) showed EGW ≥ 903 gm. Thus, it can be said that cases showed EGW ≥ 903 gm have a probability of 71.1% to have big difference between EGW and AGW (≥15%). EGW of 1069 gm was identified as another cutoff point of a better specificity on ROC curve showing 32.1% and 93.9% for sensitivity and specificity, respectively, on ROC curve. At this cutoff point, 77.9% of cases (n=67) showed EGW < 1069 gm, while 22.1% of cases (n=19) showed EGW ≥ 1069 gm. Thus, it can be said that cases showed EGW ≥1069 gm have a probability of 89.5% to have big difference between EGW and AGW (≥15%). TLW of 1587 gm was identified as cutoff point of the best specificity with the best sensitivity and specificity on ROC curve showing 56.6% and 60.6% for sensitivity and specificity, respectively, on ROC curve. At this cutoff point, 50% of cases (n=43) showed  TLW < 1587 gm, while 50% of cases (n=43) showed  TLW ≥ 1587 gm. Thus, it can be said that cases showed  TLW ≥1587 gm have a probability of 69.8% to have big difference between EGW and AGW (≥15%). TLW of 1807 gm was identified as another cutoff point of better specificity on ROC curve showing 18.9% and 93.9% for sensitivity and specificity, respectively, on ROC curve. At this cutoff point, 86% of cases (n=74) showed TLW < 1807 gm, while 14% of cases (n=12) showed  TLW ≥ 1807 gm. Thus, it can be said that cases showed TLW ≥1807 gm have a probability of 83.3% to have big difference between EGW and AGW (≥15%). Conclusion: TLV and  EGV in CT volumetry are most reliable preoperative factors that can predict big difference between EGW and AGW. Re-evaluation of CT volumetry protocol is recommended for better prediction.