BACKGROUND: Most stroke patients are unable to receive thrombolytic therapy because they do not reach a hospital within 3 hours from symptom onset. The aim of this study was to determine the factors (including knowledge of stroke) that affect the admission delay. METHODS: From May 2007 to December 2007, consecutive ischemic stroke patients presenting within 3 days from symptom onset and their relatives were interviewed about their knowledge of the following aspects of stroke: stroke warning signs, thrombolytic therapy, the 3-hour time limit for admission delay, and use of emergency medical services. Clinical data of patients were collected from medical records. RESULTS: One hundred and fifty-three patients were finally included, 37 of which (24.2%) reached our hospital within 3 hours from symptom onset. In univariate and multivariate analyses, factors independently associated with an admission delay of less than 3 hours were age (odds ratio [OR]=0.95, 95% confidence interval [CI]=0.91.0.99; p=0.008), atrial fibrillation (OR=5.02, CI=18.104.22.168; p=0.016), NIHSS score at admission (OR=1.09, CI=1.01.1.18; p=0.028), and knowledge of the 3-hour time limit (OR=3.55, CI=22.214.171.124; p=0.006). In the patients with an NIHSS score of >4 points, knowledge of the 3-hour time limit was the only independent factor associated with an admission delay of less than 3 hours. This knowledge was significantly associated with graduation from high school (p=0.038). CONCLUSIONS: Knowledge of the 3-hour time limit was the only modifiable factor that influenced an admission delay of less than 3 hours. Therefore, educating the public about stroke, including about the 3-hour time limit, could increase the ability to apply thrombolysis to acute stroke patients.