A higher resting heart rate is associated with an increased probability of cardiovascular complications and premature death in patients with type 2 diabetes mellitus. The impact of heart rate on the risk of developing microvascular complications, such as diabetic retinopathy and nephropathy, is, however, unknown. The present study tests the hypothesis that a higher resting heart rate is associated with an increased incidence and a greater progression of microvascular complications in patients with type 2 diabetes mellitus. The relation between baseline resting heart rate and the development of a major microvascular event was examined in 11 140 patients who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study. Major microvascular events were defined as a composite of new or worsening nephropathy or new or worsening retinopathy. Patients with a higher baseline heart rate were at increased risk of a new major microvascular complication during follow-up (adjusted hazard ratio: 1.13 per 10 beats per minute; 95% confidence interval: 1.07-1.20; P<0.001). The excess hazard was evident for both nephropathy (adjusted hazard ratio: 1.16 per 10 beats per minute; 95% confidence interval: 1.08-1.25) and retinopathy (adjusted hazard ratio: 1.11 per 10 beats per minute; 95% confidence interval: 1.02-1.21). Patients with type 2 diabetes mellitus who have a higher resting heart rate experience a greater incidence of new-onset or progressive nephropathy and retinopathy. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00145925. http://www.advance-trial.com/static/html/prehome/prehome.asp.