Diabetes mellitus is an important coronary artery disease risk factor. The presence of microalbuminuria, which indicates renal involvement in diabetic patients, is associated with an increased cardiovascular risk. There are suggestions that diabetic patients with microalbuminuria have more adverse risk profile such as higher ambulatory blood pressure and total cholesterol levels to account for the increased cardiovascular morbidity and mortality. QT dispersion is increasingly being recognized as a prognostic factor for coronary artery disease and sudden death. Some studies have suggested that QT dispersion is an important predictor of mortality in Type II diabetic patients. Our cross sectional study was to compare the QT dispersion and 24 hour ambulatory blood pressure monitoring between diabetic patients with microalbuminuria and those without microalbuminuria. Diabetic patients with overt coronary artery disease were excluded from the study. A total of 108 patients were recruited of which 57 patients had microalbuminuria and 51 were without microalbuminuria. The mean value of QT dispersion was significantly higher in patients with microalbuminuria than in patients without microalbuminuria (58.9 +/- 27.9 ms vs. 47.1 +/- 25.0 ms, p < 0.05). The mean 24 hour systolic and diastolic blood pressures were significantly higher in patients with microalbuminuria than in patients without microalbuminuria (129.5 +/- 12.3 mm Hg vs 122.3 +/- 10.2 mm Hg, p < 0.05 and 78.4 +/- 6.9 mm Hg vs 75.3 +/- 6.8 mm Hg, p < 0.05, respectively). Our study suggests that QT dispersion prolongation, related perhaps to some autonomic dysfunction, is an early manifestation of cardiovascular aberration in diabetic patients with microalbuminuria. The higher blood pressure levels recorded during a 24-hour period min diabetics with microalbuminuria could also possibly account for the worse cardiovascular outcome in this group of patients.