Objective To evaluate the prevalence and risk factors of microalbuminuria (MAU) in hospitalized patients. Methods 1259 hospitalized patients with detected urinary microalbumin in the year of 2012 were recruited in Tongji Hospital of Tongji University . They were divided into two groups according to the level of urinary microalbumin. 907 cases were included in normal albuminuria (NAU) group , 352 cases were in microalbuminuria group. Statistical analysis of clinical data was made in the two groups. Results Microalbuminuria prevalence of hospitalized patients was 27.9%. The age in MAU group was elder than NAU group (P<0.01), and the prevalence of diabetes mellitus and hypertension in MAU group was higher than NAU group (P<0.01). The age, gender, TG, TC, LDL-C, HDL-C, diabetes, hypertension and diabetes hypertension served as independent variables, and MAU as a dependent variable for univariate analysis. Results showed age, diabetes , hypertension and diabetes hypertension were closely related to MAU. Further multivariate analysis with logistic regression revealed that age and diabeteswere independent risk factors of MAU. Advanced age (>80 years old，OR 1.668，95% CI 1.185~2.348) and diabetes mellitus (OR 1.718，95% CI 1.334~2.211) increased the risk for MAU. Conclusions MAU is closely related to age and diabetes mellitus in hospitalized patients. Strict control of blood glucose and timely treatment are helpful to slow down the development and progression of diabetic nephropathy and cardiovascular disease.