Anticoagulation control has been associated with risk of thromboembolism and hemorrhage. Herein, we explore the relationship between anticoagulation control achieved in Left Ventricular Assist Device Patients (LVADs) and evaluate the association with risk of thromboembolism and hemorrhage. Patients (aged 19 or older) with a continuous flow LVAD placed from 2006–2012. Proportion of time spent in target range (PTTR) for INR was estimated with target range of 2.0–3.0. PTTR was categorized into PTTR>60%, PTTR≥50<60% and PTTR<50%. The relationship between PTTR and thromboembolism and hemorrhage was assessed. The 115 participants contributed 624.5 months of follow-up time. Only 20% of patients achieved anticoagulation control (PTTR >60% for INR range of 2–3). After adjusting for chronic kidney disease, history of diabetes, history of atrial fibrillation and age at implant, compared to patients with PTTR<50%, the relative risk of thromboembolism in patients with PTTR≥60% (HR 0.37, 95%CI 0.14–0.96, p=0.042) was significantly lower, but not for patients with a PTTR of ≥50<60% (HR 0.21, 95%CI 0.02–1.82, p=0.16). The relative risk for hemorrhage was also significantly lower among patients with a PTTR≥60 % (HR 0.45, 95%CI 0.21–0.98, p=0.045), but not among those with PTTR of ≥50<60% (HR 0.47, 95%CI 0.14–1.56, p=0.22). This current study demonstrates that LVAD patients remain in the INR target range an average of 42.9% of the time. To our knowledge, this is the first report with regard to anticoagulation control as assessed by PTTR and its association with thromboembolism, hemorrhage or death among patients with VADs.