Aims: It was reported that exenatide ameliorated renal injury in diabetic rats. The present study was carried out to evaluate the effect of exenatide on 24-hour urinary albumin, urinary transforming growth factor-β<sub>1</sub> (TGF-β<sub>1</sub>) and type IV collagen excretion in patients with type 2 diabetes and microalbuminuria. Methods: 31 type 2 diabetic patients with microalbuminuria were randomly allocated to receive exenatide (group Exe, n = 13) or glimepiride treatment (group Glm, n = 18) for 16 weeks. Body mass index (BMI), fasting plasma glucose, 2-hour postprandial plasma glucose, glycated hemoglobin A<sub>1c</sub>, systolic blood pressure, diastolic blood pressure, 24-hour urinary albumin, urinary TGF-β<sub>1</sub> and type IV collagen concentration were analyzed between the two treatment groups. 20 age- and BMI-matched healthy subjects were chosen as the normal control group (group NC, n = 20). Results: After 16 weeks of treatment, 24-hour urinary albumin, urinary TGF-β<sub>1</sub> and type IV collagen in group Exe were significantly lower than those of group Glm (p < 0.01), while glycemic control had no statistical difference betweenthe two groups. Conclusions: Our results indicate that exenatide reduces urinary TGF-β<sub>1</sub> and type IV collagen excretion in patients with type 2 diabetes and microalbuminuria, which may be partly contributory to its directly renoprotective role.