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Meningitis is one of the urgent medical ceases, and in spit of tramendous efforts. There is a high prevalency in various part of the world, still has got a high mortality. Rapid diagnosis is one of the best way to control the disease, and the basis for the present study is to find out the rate of occurrence of meningitis in suspicious cases. During nine-month study (Sep 1999-June 2000), 100 children with suspicious sings of meningitis referring to Taleghani children hospital were taken under medical surveillance, and LP has been carried out by the pediatrician. The samples were transferred to the laboratory and various tests has been done on the samples. On the ground of clinical and paraclinical findings 15 meningitis patients (7 bacterial, and 8 viral were diagnosed). The most abundant isolated bacteria from the CSF was Pneumococci (42.8%) and the most significant clinical finding was fever, vomiting, stiffness of neck. In all bacterial meningitis the CSF’s appearance was deeply turbid, and the average WBC in CSF was about 3200, the rate of PMN was 92%, these results had significant meaning with comparison to the viral and non-meningitis sample (P<0.001). CFS’s protein level was much more higher in bacterial meningitis, than other cases (P<0.001), and this can be used as diagnostic tool, but in spit of reduction in CSF glucose concentration, and CSF/blood glucose ratio (48% in bacterial, 70% viral, and 74% in non-meningitis), these ratios didn’t have significant meaning (P<0.4). The results of this research indicate the clinical manifestation such as fever, convulsion, vomiting turbidity of CSF, WBC count more than 500, and positive CRP, could help effectively in the diagnosis of bacterial meningitis.