To look for the etiologic agent in cerebrospinal fluids of 44 children with meningitis, Gram stain, traditional culture, latex agglutination and counterimmunoelectrophoresis were simultaneously performed. The sensitivity of all four methods was roughly equal. The outstanding importance of the Gram technique has to be emphasized, however. Differences with regard to antigen detection could be observed in patients previously treated with antibiotics, where etiologic agents could still be detected by latex agglutination and counterimmunoelectrophoresis, but not by traditional cultures. A further advantage of the two methods is that they provide results rapidly. The use of all four methods simultaneously allows for optimal results in the detection of causative organisms in cerebrospinal fluid in meningitis.