Aims A very limited number of prospective studies have reported conflicting data on the relation between heart rate and diabetes risk. Our aim therefore was to determine in a large, national, population-based cohort if heart rate predicts the development of diabetes. Methods The Australian Diabetes Obesity and Lifestyle study followed up 6537 people over 5years. Baseline measurements included questionnaires, anthropometrics and blood and urine collection. Heart rate was recorded in beats per min (Dinamap). An oral glucose tolerance test was performed at baseline and follow-up, and diabetes was defined using World Health Organization criteria. Results A total of 5817 participants were eligible for analysis, 221 of whom developed diabetes. Compared with participants with a heart rate <60bmin1, those with a heart rate 80bmin1 were more likely to develop diabetes (odds ratio1.89, 95%CI 1.073.35) over 5years, independent of traditional risk factors. This relationship was highly significant, particularly in non-obese men (odds ratio5.61, 95%CI 1.7517.98), but not in their obese counterparts or in women. Conclusions Resting heart rate is associated with an increased risk of diabetes over a 5-year period, particularly among non-obese men. This suggests that sympathetic overactivity may be a contributing factor to the development of diabetes, and that resting heart rate may be useful in predicting risk of Type2 diabetes in non-obese men.