Objective: To investigate the renal function state and risk fators of reduced renal function among aged inpatients. Methods: The clinical data of inpatients aged 60 years or over were collected. The estimated glomerular filtration rate (eGFR) was calculated by abbreviated MDRD equation. The renal function state and risk fators of reduced renal function were analyzed. Results: In all 1051 subjects with eligible data, the mean eGFR was 71.0±24.8 ml·min^-1·(1.73m²)^-1 and the incidence rate of reduced renal function was 31.1%, the incidence rates of proteinuria, hematuria and leucocyturia were respectively 11.8%, 6.6% and 8.7%. The eGFR values were respectively 83.4±28.4, 72.2±22.9, 67.8±24.3 and 58.8±29.1 ml·min^-1·(1.73m²)^-1 in the group of 60-69, 70-79, 80-89 and ≥ 90 years old (F=15.101, P=0.000), while the incidence rates of reduced renal function were separately 12.8%, 27.0%, 37.8% and 51.7% in the above age groups (χ²=36.143, P=0.000). Binary logistic regression analysis showed that hyperuricemia (OR=4.62, P=0.000), proteinuria (OR=3.96, P=0.000), urinary tumor (OR=2.92, P=0.015), anemia (OR=2.45, P=0.000), stroke (OR=1.96, P=0.000), hypertension (OR=1.83, P=0.006), renal cyst (OR=1.64, P=0.018), female (OR=1.54, P=0.015), coronary artery disease (OR=1.53, P=0.008) and age (OR=1.05, P=0.000) were the risk factors of reduced renal function. Conclusions: The incidence rates of reduced renal function was high in elderly patients and the eGFR values decreased by age, while the incidence rates of reduced renal function increased. Treatment and control of comorbidities might contribute to slow the decline of renal function.