Purpose: We assessed Red Cell Distribution Width (RDW) levels at hospital admission and determined whether RDW could serve as a predictor of disability prognosis in patients with acute ischemic stroke. Research Methodology: A retrospective cohort study was conducted using data from the stroke registry at Bethesda Hospital, Yogyakarta. RDW levels were measured upon hospital admission. Functional disability at 30 days post-stroke was evaluated using the modified Rankin Scale and analyzed statistically. Results: Elevated RDW levels were observed in 20.8% of patients. Receiver operating characteristic analysis identified an optimal RDW cutoff value of 14.15%, with an area under the curve of 0.689 (p=0.009). At 30 days after stroke onset, 20% of patients had poor functional outcomes. Bivariate analysis demonstrated a significant association between high RDW levels and poor disability outcomes (p=0.001; OR=14.333). Multivariate logistic regression analysis confirmed that elevated RDW was an independent predictor of 30-day post-stroke disability (OR=4.287; 95% CI: 2.036–9.029; p<0.001). Conclusions: Elevated RDW at admission is significantly associated with poorer functional outcomes in patients with acute ischemic stroke and may serve as a useful prognostic biomarker. Limitations: This study relied on secondary data, limiting control over patient conditions and measurement quality. The study population predominantly included mild-to-moderate stroke cases, and potential confounding factors, such as comorbidities, were not evaluated. Contributions: These findings may enhance prognostic accuracy and support the development of clinical tools for predicting post-stroke disability.