Diabetes mellitus (DM) is an independent risk for cardiovascular disease. Furthermore, patients with DM have increased risk for ventricular arrhythmia that is thought to be secondary to coronary artery disease (CAD) or congestive heart failure (CHF). We hypothesized that DM may cause ventricular arrhythmias independent of CAD or CHF. Using a large database, we evaluated the occurrence of ventricular fibrillation in patients with DM adjusting for CAD and CHF. We used patient treatment files (PTF), documents of inpatients' admissions containing discharge diagnoses (ICD-9 codes) from all Veterans Health Administration Hospitals. The patients were stratified in two groups: ICD-9 code for DM (293 124) and a control group with ICD-code for hypertension (HTN) but no DM (552 623). ICD-9 codes for ventricular fibrillation were used for this study. We performed uni- and multivariant analysis adjusting for comorbid conditions. Ventricular fibrillation was present in 563 (0.2%) vs 781 (0.1%) in the control group. Using multivariate analysis, DM remained independently associated with ventricular fibrillation (odds ratio: 1.7; confidence interval: 1.5-1.9; P < 0.000). Patients with DM have significantly higher prevalence of ventricular fibrillation independent of CAD or CHF, which in part may explain the higher risk of sudden death in patients with DM.