The clinical frailty scale (CFS) evaluates the level of frailty based on clinical examination, comorbidities, and functional and activity levels of older patients. However, there are many difficulties for internists in evaluating frailty with this scale. Therefore, simplifying the CFS with good design and application is required for better treatment outcomes. Our study was conducted to design and evaluate the correlation of a simplified clinical frailty scale (sCFS) with CFS in older patients. We undertook a cross-sectional analysis involving 279 older patients, which comprised two steps. Step 1 involves the implementation of sCFS, a protocol that has been endorsed by the Geriatrics Professional Council (GPC). Step 2 entails the enrollment of older patients for frailty assessment using sCFS, comparing it with CFS. The study was conducted on 279 older patients; the average age was 75.7 ± 8.4 (years old), and men accounted for 34.8%. There was a high correlation between the sCFS and CFS (Pearson's r = 0.996; p < 0.001). The similarity of the sCFS to the CFS was very high, with Kappa coefficient = 0.984 (p < 0.001). Compared with the CFS, the sCFS had a Youden index of 98% with 100% sensitivity and 98% specificity assessed through the receiver operating characteristic (ROC) with the CFS threshold of 5. The sCFS can be used to assess frailty with high sensitivity and specificity.