Purpose : The purpose of this study was to evaluate the usefulness of computed tomography(CT) and magneticresonance imaging(MRI) in experimental bacterial meningitis. Materials and Methods : CT and MR images ofexperimental bacterial meningitis were obtained after inoculation of 1ml suspension of 106/ml Staphylococcusaureus directly into the supratentorial arachnoid space of 18 New Zealand white rabbits. Each animal was studiedwith both Pre-enhanced and post-enhanced CT and MRI at 12, 24, 48 hours and 1 week. Cerebrospinal fluid of all of18 rabbits were sampled and cultured for bacterial growth. Results : All of 18 rabbits had the clinical symptomssuch as neck stiffness and anorexia within 24 hours after the inoculation. Cerebrospinal fluid cultures werepositive for Staphylococcus sureus growth. Gd-enhanced MRI exhibited diffuse enhancement along the thickenedsupratentorial meninges earlier than CT. in Gd-enhanced MRI, the mean contrast enhancement ratio(CER) atsupratentorial meninges increased to 1.93 at 12 hours and 2.99 at 24 hours from 1.06 at 0 hour. Histologicevaluation demonstrated inflammatory cell infiltration into the meninges. MRI also identified the complications ofmeningitis such as ependymitis and hydrocephalus more effectively than CT. Conclusion: These results indicatedthat Gd-enhanced MRI detected earlier the abnormal findings of bacterial meningitis and evaluated more effectivelythe complications of meningitis compared with CT. MRI was more useful than CT in evaluation of the bacterialmeningitis.