Objective: To explore the patient and hospital related determinants of adherence to early antithrombotic therapy among patients with acute ischemic stroke (AIS). Methods: AIS patients aged 50 years old or above who were eligible for early antithrombotic therapy, were included from the China National Stroke Registry Ⅱ (CNSR Ⅱ) project. Characteristics related to patients and hospitals were collected. Univariate analysis method was conducted to explore the correlation between hospital or patient-related determinants and early antithrombotic therapy. A 2-level logistic regression model was set up to identify patient and hospital-related variables that were associated with the adherence to early antithrombotic therapy, with patient as level 1 and hospital as level 2. Results: A total of 16 910 patients were included in the study, with 14 332 (84.75%) of them having received early antithrombotic therapy. Results from the univariate analysis showed that the patient determinants to early antithrombotic therapy would include age, type of health insurance, average income and history of dyslipidemia. Hospital determinants would include factors as: level and region of the hospital, academic status, with/without stroke unit, quality control on single disease and the percentage of neurological beds in total beds (P<0.05). Data on multilevel model showed that the patient-related determinants on early antithrombotic therapy would include age, gender, average income, history of hypertension, National Institutes of Health Stroke Scale (NIHSS) score at admission while hospital related determinants would include percentage of neurological beds in total beds, and region of the hospital (P<0.05). Conclusions The quality of a hospital was associated with the adherence to early antithrombotic therapy. AIS patients at advanced age or with high NIHSS score at admission should be paid more attention.