Objectives: To assess the relationship of variation of blood pressure and neurological deterioration (ND) in ischemic stroke patients. Methods: We recruited patients with the fi rst-ever ischemic stroke at a teaching hospital. The National Institutes of Health Stoke Score (NIHSS) of each patient was monitored for 2 months. ND was defi ned as an increase of ≥ 2 points in NIHSS during the fi rst 7 days after stroke. Blood pressure was measured every 6 hours for fi rst 7 days. We analyzed blood pressure data in the fi rst 36 hours to study the relationship between variation of blood pressure and ND. Successive variation of systolic (svSBP) and diastolic (svDBP) blood pressure was calculated as svSBP= |SBPn+1 – SBPn | and svDBP= |DBPn+1 – DBPn | respectively. The largest svSBP in the fi rst 36 hours of hospitalization or before ND was defi ned as maximum variation of systolic blood pressure (maxvSBP). Then, the mean variation of systolic (mvSBP) and diastolic (mvDBP) blood pressure was calculated as mvSBP= svSBP/N and mvDBP= svDBP/N respectively. Results: A total of 121 patients were included in this study, and 38 of them had ND. The mvSBP was higher in the ND Group (17.9±8.4 mmHg vs. 13.7±4.4 mmHg, p=0.006) but the difference in mvDBP did not reach statistical signifi cance (9.8±3.5mmHg vs. 8.6±3.0 mmHg p=0.06). The ND Group had a larger maxvSBP (35.2±17.2 vs. 27.6±11.6 mmHg, p =0.01), which was more frequently over 30mmHg than that in the stable group (P=0.02). Conclusions: A large svSBP is associated with an increased risk for ND. The study highlights the importance of close monitoring of blood pressure in ischemic stroke patients.