Stroke remains a major cause of mortality and disability in low- and middle-income countries, where access to advanced diagnostic tools for early severity assessment is often limited. This hospital-based cross-sectional study aimed to examine the association between routinely measured blood biomarkers and stroke severity among newly diagnosed stroke patients in Bangladesh. The study was conducted at a tertiary care neurological center in Dhaka from January to December 2024 and included 200 adult patients with first-ever ischemic or hemorrhagic stroke confirmed by clinical evaluation and neuroimaging. Sociodemographic, clinical, and lifestyle-related information was collected using a pretested questionnaire. Stroke severity was assessed at admission using the National Institutes of Health Stroke Scale (NIHSS). Routine laboratory parameters, including complete blood count, fasting blood glucose, serum creatinine, fasting lipid profile, and serum electrolytes, were analyzed as part of standard clinical care. Ischemic stroke was the predominant subtype (75.5%), and most patients presented with mild stroke severity (75.0%). Hypertension and diabetes mellitus were the most common comorbidities. Abnormalities in routine biomarkers were frequent, including anemia, leukocytosis, dyslipidemia, and altered renal and electrolyte parameters. Increasing stroke severity was significantly associated with elevated white blood cell count, raised serum creatinine, adverse lipid profiles, abnormal potassium levels, and altered bicarbonate concentrations, while hemoglobin and serum sodium showed no significant association. Stroke severity also differed significantly by stroke subtype, with hemorrhagic stroke patients presenting with higher NIHSS scores. These findings indicate that routinely available blood biomarkers are significantly associated with stroke severity and may serve as practical adjuncts to clinical assessment for early risk stratification in resource-limited healthcare settings.