OBJECTIVE To investigate the effects of individualized dosing regimen on blood trough concentration of vancomycin and renal function in critically ill patients. METHODS According to relevant guidelines and the results of Vancomycin Calculator， clinical pharmacists formulated an individualized dosing regimen of vancomycin including loading dose and maintenance dose for critically ill patients based on the two independent variables of body weight and creatinine clearance rate. Using the method of retrospective study， patients who were admitted to the department of intensive care unit （ICU） of the Second Affiliated Hospital of Guangzhou Medical University and used the regimen from July 2018 to December 2021 were selected as the trial group， and patients who were treated with vancomycin and received blood drug concentration monitoring in ICU from January 2015 to June 2018 were recruited in the control group. The difference in trough concentration distribution and the incidence of acute kidney injury （AKI） after medication were compared between the two groups， the change of serum creatinine before and after medication in the trial group was analyzed. RESULTS Totally 197 patients were included in the trial group and 144 patients were in the control group. There was no significant difference between the two groups in the clinical information （gender， age， body weight， acute physiology and chronic health evaluation Ⅱ score， the proportion of patients with renal insufficiency， etc.） （P＞0.05）. The proportions of major infection sites （including lung， urinary， abdominal， blood and central nervous system） and treatment type （target or empirical treatment） also had no significant difference between the two groups （P＞0.05）. There was no significant difference in the attainment rate of ideal trough concentration （15-20 μg/mL） and the proportion of patients with trough concentration　＞20 μg/mL between the two groups （P＞0.05）， while the attainment rate of target trough concentration （10-20 μg/mL） and the proportion of patients with trough concentration ＜10 μg/mL were significantly different between the two groups （P＜0.05）. The attainment rate of target trough concentration in patients with chronic renal insufficiency in trial group was significantly higher than that in control group （P＜0.05）. There was no significant difference in the incidence of AKI and vancomycin-associated AKI between the two groups （P＞0.05）. In the trial group with medication duration ≥7 days ， the level of serum creatinine on the 7th day of treatment was increased significantly， compared with that on the 3rd day of treatment （P＜0.05）. CONCLUSIONS This individualized dosing regimen can improve the attainment rate of target trough concentration of vancomycin in critically ill patients， especially those with chronic renal insufficiency， during the first standardized monitoring， and not increase the risk of renal injury compared with previous empirical medication.