Background: and Purpose Endovascular treatment (EVT) is the preferred treatment option in eligible acute ischemic stroke (AIS) patients with a large vessel occlusion of the anterior circulation. Several comorbidities have been identified that can affect clinical outcomes. Various studies have investigated the association between anemia and clinical outcome and found conflicting results. The aim is to investigate the association between pre-EVT anemia and clinical outcomes at different time points post-EVT, primarily focusing on the National Institutes of Health Stroke Scale (NIHSS) at 24–48 hours. Methods: We prospectively included 560 AIS patients who received EVT in the Maastricht University Medical Center+. Hemoglobin levels (Hb; g/dL) were determined on admission. Hb levels were also categorized into two groups: anemia (male: Hb ≤12.9 g/dL; female: Hb ≤11.9 g/dL) and no anemia. Multiple imputation was used to handle missing data. Multivariable regression was used to investigate the association between anemia or Hb levels and clinical outcomes. Results: Anemia was present in 26% of the patients. Multivariable regression did not show a significant association between anemia or Hb levels and NIHSS at 24–48 hours (adjusted β [aβ]anemia: 1.44, 95% confidence interval [CI]: -0.47 to 3.36; aβHb: -0.37, 95% CI: -0.88 to 0.13). However, multivariable regression showed significant associations with modified Rankin Scale (adjusted common odds ratio [acOR]anemia: 1.66, 95% CI: 1.12 to 2.48; acORHb: 0.83, 95% CI: 0.75 to 0.93) and poor functional outcome at 90 days (adjusted OR [aOR]anemia: 2.09, 95% CI: 1.21 to 3.63; aORHb: 0.80, 95% CI: 0.69 to 0.92). Conclusion Anemia was not independently associated with early neurological deficit (NIHSS) post-AIS, suggesting it is more suitable as a general frailty marker.