Meningitis is a life-threatening disease because of the inflammation's proximity to the brain and spinal cord. Untreated bacterial meningitis is almost always fatal; therefore it is important to differentiate bacterial meningitis from aseptic meningitis early. Objectives: To evaluate the role of Extradomain A (EDA) Fibronectien in diagnosis of meningitis and differentiation between bacterial and aseptic causes. Methods: This study was conducted on total number of 150 patient aged (18-60years old) suspected to have meningitis, 100 patients were excluded due to trauma, cerebrovascular stroke and CNS tumors. Patients were classified according to the CSF findings into 20 patients as bacterial meningitis group (group1) and 20 patients as aseptic meningitis group (group II). In addition to 10 cases of matched age and sex, free from any CNS diseases serving as control group (group III). All subjects were subjected to full history taking, clinical examination, laboratory investigations, and measurement of plasma and CSF EDA- FN levels using ELISA method. Results: CSF EDA- FN level at a cut off value less than 14.2mg/l have a sensitivity of (90%) and specificity of (85%) to differentiate between bacterial and aseptic meningitis (P-Value <0.001), while plasma EDA- FN level at a cut off value more than 2.45mg/l have a sensitivity of (75%) and specificity of (50%) to differentiate between bacterial and aseptic meningitis (p- value <0.05). Conclusion: CSF and plasma EDA-Fibronectin level can be used as a diagnostic marker in patients with meningitis. It can also differentiate between bacterial and aseptic meningitis.