Background: Arterial stiffness is an independent determinant of cardiovascular and cerebrovascular risks. The relationship between the increase in arterial stiffness parameters and the severity of stroke has been shown in previous studies. We aimed to investigate the association between clinical improvement and changes in arterial stiffness parameters in patients presenting acute ischemic stroke. Methods: A total of 107 patients were enrolled in this study. On the first and seventh day of the hospitalization, 24 h non-invasive blood pressure was monitored and arterial stiffness parameters were measured. The National Institutes of Health Stroke Scale (NIHSS) was used to determine the severity of stroke, and the Modified Rankin Scale was used to determine dependency and to evaluate functional improvements. Results: Arterial stiffness parameters of augmentation index (AIx@75) and pulse wave velocity (PWV) were significantly higher in patients who died during hospitalization than patients who were discharged (respectively p <0.001, p = 0.04). In the group with clinical improvement, PWV values measured on the seventh day were significantly lower than PWV values measured on the first day (p = 0.032). When the changes in PWV value measured on the first and seventh day for both groups were analyzed using mixed ANOVA test, p value were significant (p = 0.033). Multivariate binary logistic regression analyses showed that negatively change in PWV and CDBP independently predicts the clinical improvement. Conclusions: Increased AIx@75 and PWV appear to be associated with higher in-hospital mortality rates in patients with acute ischemic stroke. Additionally, clinical improvement in patients with ischemic stroke is associated with a decrease in PWV.