PurposeTo investigate the predictive role of pre-thrombolytic high sensitivity C-reactive protein (hs-CRP) on the safety and efficacy of intravenous thrombolysis in patients with acute ischemic stroke (AIS).MethodsPatients with AIS who underwent intravenous thrombolysis with recombinant plasminogen activator (rtPA) or urokinase without endovascular therapy from June 2019 to June 2022 were retrospectively analysed. All patients were grouped into two groups (high or low hs-CRP group) according to the median value of hs-CRP before intravenous thrombolysis. The baseline NIHSS, NIHSS changes before and after thrombolysis (ΔNIHSS), the rate of good thrombolysis response (NIHSS decreased ≥ 2 points from baseline), the rate of any intracranial hemorrhage, age, sex, hypertension, diabetes, uric acid and platelet count were compared between the two groups. Logistic regression analysis was performed to identify possible prognostic factors for a good thrombolysis response.ResultsA total of 212 patients were included in the analysis, with a mean age of 66.3 ± 12.5 years. In total, 145 patients received rtPA, and 67 patients received urokinase. Patients were divided into a high hs-CRP group (> 1.60 mg/L) and a low hs-CRP group (≤ 1.60 mg/L) according to the median hs-CRP level (1.60 mg/L). The ΔNIHSS of the high hs-CRP group was significantly smaller than that of the low hs-CRP group (0 [-1 ~ 0] vs. -1 [-2 ~ 0], P < 0.05). The good rate of thrombolysis response in the high hs-CRP group was significantly lower than that in the low hs-CRP group (21.9% vs. 36.5%, P < 0.05). Similar results were shown in the rtPA subgroup between the high and low hs-CRP groups but not in the urokinase subgroup. Logistic regression analysis showed that hs-CRP > 1.60 mg/L was negatively correlated with a good thrombolysis response rate (OR = 0.496, 95% CI = 0.266–0.927, P = 0.028).Conclusionhs-CRP > 1.6 mg/L may serve as a poor prognosis predictive factor for patients with AIS receiving intravenous thrombolysis. However, due to the small sample size of this study, further studies are needed to verify our results.