['Evaluating recombinant tissue plasminogen activator utilization rates is important, as many studies have demonstrated that administration of recombinant tissue plasminogen activator to qualified patients significantly improves prognosis.', 'We investigated recent trends in the utilization and outcomes of administration of intravenous recombinant tissue plasminogen activator in the United States using the National Inpatient Sample between 2001 and 2008.', 'We identified patients with a primary diagnosis of acute ischemic stroke who underwent treatment with intravenous recombinant tissue plasminogen activator and studied utilization rates and clinical outcomes: discharge to long-term facility (morbidity), in-hospital death (mortality), and intracranial hemorrhage. Information on demographics, hospital characteristics, and comorbidities was collected. A multivariate logistic regression analysis was performed to determine independent predictors of morbidity, mortality, and intracranial hemorrhage.', 'Intravenous recombinant tissue plasminogen activator utilization increased from 1·3% in 2001 to 3·5% in 2008. On multivariate analysis, variables associated with increased morbidity after intravenous recombinant tissue plasminogen activator administration included advanced age (P\u2009<\u20090·001), female gender (P\u2009<\u20090·001), and comorbidities of atrial fibrillation (P\u2009<\u20090·001) and hypertension (P\u2009<\u20090·001). Increased mortality was associated with increased age (P\u2009<\u20090·001) and comorbidities of atrial fibrillation, congestive heart failure, coronary artery disease, and diabetes (P\u2009<\u20090·001 for all comorbidities).'] Is utilization of intravenous thrombolysis increasing in the United States?