Background: Hematological parameters, such as white blood cell count (WBC), mean platelet volume (MPV), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and
WBC to MPV ratio (WMR), could provide data in prognosis, risk stratification, and optimal management in patients with acute coronary syndromes. Aim: We aimed to investigate the prognostic value of hematological parameters and their relationship with the TIMI risk score in non-ST elevation myocardial infarction (NSTEMI) patients. Material and Methods: A total of 259 adult patients with NSTEMI were included in this retrospective and observational cohort study. During a 1-year follow-up period, the efficacy of the main hematological parameters in predicting major adverse cardiovascular events (MACE) and their correlation with the TIMI risk score was analyzed. Results: Among the 259 patients, 188 (72.6%) were male, and the mean age was 60.4 ± 11.9 years. MACE was observed in 60 patients (23.2%). Elevated baseline levels of WBC, neutrophils, NLR, PLR, and WMR were associated with MACE development throughout the 1-year follow-up. Moreover, WBC, WMR, and NLR were correlated with the TIMI risk score. When the predictive power of these parameters for MACE was evaluated by ROC analysis, the AUC values for WBC, WMR, and NLR were 0.670 (95% CI 0.590–0.750), 0.666 (95% CI 0.582–0.746), and 0.689 (95% CI 0.610–0.767), respectively. Conclusion: WBC, NLR, and WMR predicted MACE in NSTEMI patients and were consistent with the TIMI risk score. On this basis, they could provide supportive data for early risk stratification and optimized therapeutic approach, particularly in high-risk patients.