Introduction: Sodium-glucose cotransporter 2 inhibitors (SGLT2Is) have beneficial effects on the renal function of chronic kidney disease (CKD) patients, although the types of patients suitable for this treatment remain unclear. Methods: A retrospective observational study was conducted on CKD patients who were treated with SGLT2I in our department from 2020 to 2023. The estimated glomerular filtration rate (eGFR) just before treatment was defined as the baseline and the difference between pre-and post-treatment eGFR slopes were used to compare the improvement of renal function. Logistic regression analysis was used to evaluate the independent factors for its improvement. Results: A total of 128 patients were analyzed (mean age: 67.2 years; number of women: 28 [22%]). The mean eGFR was 42.1 mL/min/1.73 m2, and urine protein was 0.66 g/gCr. The eGFR slopes of patients with an eGFR <30 mL/min/1.73 m2 were improved significantly after treatment (−0.28 to −0.14 mL/min/1.73 m2/month, p < 0.001) but were worsened in patients with an eGFR ≥30 mL/min/1.73 m2. Logistic analysis for the improvement in eGFR slopes showed that women (odds ratio [OR], 5.63; 95% confidence interval [CI], 1.16–27.3; p = 0.03), use of mineralocorticoid receptor antagonists (OR, 11.79; 95% CI, 1.05–132.67; p = 0.012) and rapid decline of eGFR before treatment (OR, 12.8 per mL/min/1.73 m2/month decrease in eGFR; 95% CI, 3.32–49.40; p < 0.001) were significant independent variables. Conclusion: SGLT2Is may have beneficial effects, especially for rapid decliners of eGFR, including advanced CKD.