Objective: We analyzed a national cohort of suitable ECD candidate prediction (n=30,183) using KONOS data. In recent study, we developed Korean kidney donor profile index (K-KDPI) including 4 donor factors (age, height, diabetes, and serum creatinine), which were independently associated with graft failure. The higher K-KDPI group (≥70%) is defined as ECD, which showed worse graft survival than the lower K-KDPI group (<70%), SCD. Methods: Candidates with short waiting time (<7 years) and negative PRA had better post-transplant patient survival by receiving ECD kidneys compared to dialysis-or-receiving SCD kidneys. KT with a kidney of K-KDPI 70-79% was associated with transplant benefit for patients who were negative PRA and listed with short waiting time. KT with a kidney of K-KDPI 80-89% was associated with significantly better survival in patients who were diabetic, aged 40 or older with short waiting time and negative PRA. KT with a kidney of K-KDPI 90-100% was associated with significant survival benefit in patients who were male, diabetic, aged 40 or older with negative PRA and non-O blood type.  Results: In conclusion, the K-KDPI and criteria of suitable candidates for ECD are expected to improve assessing quality of deceased donor kidneys and efficient utilization of ECD kidneys in Korea with long waiting time. Conclusions: Objective: Organ shortages have led to expansion in the acceptance criteria for deceased donors. Although introduction of criteria of expanded criteria donor (ECD) and standard criteria donor (SCD) has been useful for making decisions about accepting organ offers, the prognostic value of the dichotomous ECD criteria has been reported to be inadequate. Moreover, it is unclear who can get survival benefits by receiving ECD kidney transplantation (KT) compared to continuous waiting for SCD transplantation. Here, we proposed criteria of candidates suitable for ECD transplantation using a new prognostic index for deceased donor kidney in Korea.  Methods: We analyzed a national cohort of suitable ECD candidate prediction (n=30,183) using KONOS data. In recent study, we developed Korean kidney donor profile index (K-KDPI) including 4 donor factors (age, height, diabetes, and serum creatinine), which were independently associated with graft failure. The higher K-KDPI group (≥70%) is defined as ECD, which showed worse graft survival than the lower K-KDPI group (<70%), SCD. Results: Candidates with short waiting time (<7 years) and negative PRA had better post-transplant patient survival by receiving ECD kidneys compared to dialysis-or-receiving SCD kidneys. KT with a kidney of K-KDPI 70-79% was associated with transplant benefit for patients who were negative PRA and listed with short waiting time. KT with a kidney of K-KDPI 80-89% was associated with significantly better survival in patients who were diabetic, aged 40 or older with short waiting time and negative PRA. KT with a kidney of K-KDPI 90-100% was associated with significant survival benefit in patients who were male, diabetic, aged 40 or older with negative PRA and non-O blood type.  Conclusions: In conclusion, the K-KDPI and criteria of suitable candidates for ECD are expected to improve assessing quality of deceased donor kidneys and efficient utilization of ECD kidneys in Korea with long waiting time.