Objective To search evidence of angiotensin-converting-enzyme inhibitors for microalbumin-uria in type 2 diabetes for guiding clinical practice. Methods We searched MEDLINE （ 1970 -Jun. 2005 ） to identify randomized controlled trials （RCT）of the effect on angiotensin-converting-enzyme inhibitors to prevent microalbuminuria in type 2 diabetes. Results One RCT （n =1 204）was identified. The result showed that angiotensin-converting-enzyme inhibitors were significantly more effective in prevention of microalbuminuria than other medicines in type 2 diabetes. However, angiotensin-converting-enzyme inhibitors may increase the risk of cardiac mortality. We explained the evidence to patients and they were satisfied with our explanation. Conclusions Angiotensin-converting-enzyme inhibitors can decrease the incidence of microalbuminuria in patients with type 2 diabetes and hypertension.