Background and purpose Reperfusion therapy is the mainstay of treatment for acute ischaemic stroke (AIS); however, little is known about the use of reperfusion therapy and time delay amongst immigrants. Methods This is a Danish nationwide register-based cohort study of patients with AIS aged >= 18 years (n = 49,817) recruited from 2009 to 2018. Use of reperfusion therapy (intravenous thrombolysis and/or mechanical thrombectomy) and time delay between immigrants and Danish-born residents were compared using multivariable logistics and quantile regression. Results Overall, 10,649 (39.8%) Danish-born residents and 452 (39.0%) immigrants with AIS were treated with reperfusion therapy in patients arriving