Objective To examine the compliance of and factors affecting target attainment of serum trough concentration of norvancomycin in ICU patients,and the effects of different trough concentrations on clinical efficacy and renal impairment.Methods Adult patients admitted to the Department of Critical Care Medicine of Huangshan People's Hospital and receiving intravenous infusion of norvancomycin from January 2020 to December 2022 were included.The dosing regimens and steady-state trough concentrations of norvancomycin were analyzed.The clinical efficacy and renal impairment were compared between different trough concentration levels.The compliance of trough concentration in critically ill patients with different renal functions was examined.Logistic regression analysis was performed to profile the factors possibly affecting the trough concentration of norvancomycin.Results A total of 97 patients were included.The target serum trough concentration(10-20 mg/L)was reached in only 33.0％(32/97)of the critically ill patients.The serum trough concentration was below the target in 51.5％(50/97)of the patients,above the target in 15.5％of the patients.The clinical cure rate and incidence of renal impairment were significantly different among the three groups of patients with different trough concentrations(P＜0.05).The compliance with target serum trough concentration varied with different renal function tests(P＜0.05).Augmented renal clearance and normal renal function were associated with trough concentrations lower than the target.As renal dysfunction got worse,serum trough concentration was more probably higher than the target(P＜0.05).Univariate analysis showed that daily dose,age,gender,height,weight,body mass index(BMI),APACHE Ⅱ score,sequential organ failure assessment(SOFA)score,blood creatinine,urea nitrogen,procalcitonin,concomitant septic shock,and use of norepinephrine were significantly correlated with trough concentrations of norvancomycin(P＜0.05).Multivariate logistic regression analysis indicated that age,SOFA score,blood urea nitrogen,gender,and norepinephrine use were independent factors affecting the serum trough concentration of norvancomycin(P＜0.05).Conclusions The serum trough concentration of norvancomycin varied with renal function states in ICU patients.It is difficult to achieve the steady-state target trough concentration(10-20 mg/L).The clinical cure rate is lower when the trough concentration is lower than the target.As the trough concentration increases,the incidence of renal impairment increases.Age,SOFA score,urea nitrogen,gender,and norepinephrine use are independent factors affecting the serum trough concentrations of norvancomycin.