In the Netherlands in 2010, 11% of patients with ischemic stroke received intravenous thrombolysis (IVT), varying from 4 to 26% between hospitals. The aim of this study was to investigate variation in clinical practice and organization of IVT in relationship to performance and outcome. In all 84 Dutch hospitals performing IVT, a stroke neurologist was approached using a web-based survey. The response rate was 82%. The study showed considerable variation. For example, door-to-needle time ranged from 25 to 80 min. High blood pressure was actively lowered before performing IVT by 57% of neurologists, while 35% chose to wait. 28% started IVT without knowledge of laboratory results. Better follow-up data are needed to see whether this variation results in differences in outcome.