Ischemic stroke (IS) is a major cause of death and disability, with hemorrhagic transformation (HT) representing a serious complication that worsens prognosis. Identifying cost-effective biomarkers for predicting HT is a current research priority, with various hematologic indices under investigation. Over a 10-year period, 1,426 acute IS patients at the University of Debrecen received intravenous thrombolysis, and autopsies were performed in 98 deceased cases. HT was confirmed in 46 cases, and complete blood counts were used to calculate multiple hematologic ratios. Results showed that low platelet count, as well as RPR, WPR, and NPR, were significantly associated with HT, while other indices such as PLR, NLR, and LMR were not. These findings suggest that platelet-related markers may help predict HT risk and guide secondary stroke prevention strategies.