Dengue fever, a mosquito-borne arboviral infection, remains a critical public health concern in tropical and subtropical regions worldwide. This cross-sectional study, conducted at Santosh Hospital—a tertiary care center—aims to investigate the relationship between platelet count, leukocyte count, and the duration of hospitalization among dengue patients presenting with thrombocytopenia. A total of 200 laboratory-confirmed dengue cases admitted between September 2022 and October 2023 were analyzed. Clinical profiles and hematological parameters, including platelet and total leukocyte counts, were systematically assessed to evaluate their prognostic significance. Statistical analysis revealed a strong inverse correlation between platelet count and length of hospital stay (r = –0.65, p < 0.01), indicating that lower platelet levels are significantly associated with prolonged hospitalization. Additionally, leukopenia was observed in 62.5% of patients and demonstrated a moderate positive correlation with increased hospital stay (r = 0.52, p < 0.01). Multivariate regression analysis further identified both thrombocytopenia and leukopenia as independent predictors of extended inpatient care, with platelet depletion showing a more pronounced effect. Moreover, severe clinical manifestations—including dengue hemorrhagic fever, dengue shock syndrome, and major bleeding events—were more prevalent among patients requiring extended hospitalization. These findings underscore the critical role of hematological indices in predicting disease severity and duration of hospitalization in dengue infection. Early identification and close monitoring of these parameters are essential for timely clinical intervention, improved patient outcomes, and optimal utilization of healthcare resources.