Background: About one third of stroke patients have renal dysfunction. Effect of renal dysfunction on outcome of intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) has not been determined in Asia using patients without IVT as comparators. The aim of this study was to examine the interaction between renal dysfunction and IVT on the outcomes in AIS patients admitted within 4.5 hours of onset in a multicenter stroke registry of Taiwan. Methods: We identified all consecutive AIS patients admitted within 4.5 hours of onset between 2007 and 2013. Renal dysfunction was defined by an estimated glomerular filtration rate less than 60 mL/minute/ 1.73 m(2) on initial admission. Patients older than 80 years of age and a National Institute of Health Stroke Scale score less than 4 or greater than 25 were excluded. The primary outcome was a modified Rankin Scale score 3-6 at 3 months. We determined the effect of IVT and renal dysfunction on outcome in a multivariate analysis. Results: Of the 929 patients analyzed, 39% had renal dysfunction, and 51% received IVT. Primary outcomes occurred in 45% versus 41% of patients with and without renal dysfunction, respectively, (P = .197). In a multivariate analysis, the odds ratios (95% confidence interval; P value) of IVT and renal dysfunction for primary outcome were .70 (. 51-. 96; P = .029) and .97 (. 71-1.33; P = .865), respectively. No significant interaction was noted between IVT and renal dysfunction (P = .218). Conclusions: Renal dysfunction did not modify the effect of IVT for AIS and should not be a reason for withholding treatment from otherwise-eligible patients.