Objective: The Malaysian Ministry of Health Clinical Practice Guideline 2018 recommends the clinical use of the CKD-EPI equation instead of the MDRD equations. This study aims to examine mean eGFR and prevalence of chronic kidney disease (CKD) using both equations based on different age groups and to ascertain inter-rater agreement between both equations, particularly in the elderly in a tertiary hospital in Terengganu, Malaysia. Method: Serum creatinine results were extracted from the lab information system (LIS) for a 1-year duration in a patient more than and equal to 18 years old (≥18 years old). The first creatinine results from 69,329 people were used to estimate GFR using both equations. The mean eGFR, prevalence of the CKD and agreement between those two equations were compared. Result: In comparison with the MDRD equation, CKD-EPI revealed lower mean eGFR (82.63 vs 85.42 mL/min/1.73m², p<0.001) and reduce in the prevalence of the chronic kidney disease (CKD) (25.7% vs 28.4%). When subdivided by age, the prevalence of CKD reduced in the age group 18-79 years but increased in the elderly age >80 years. The numerical agreement of eGFR was excellent (ICC = 0.883), and the categorical agreement of CKD was almost perfect in all age groups. (ƙ= 0.932). Conclusion: CKD-EPI equation reduces the prevalence of CKD in young people and increases prevalence in the elderly (>80 years old). However, the CKD-EPI equation is an appropriate alternative to the MDRD equation for all age groups, including the elderly. Further validation studies involving a large multiethnic and adequate elderly population in Malaysia are much needed.