In 52 children with meningitis caused by Hemophilus influenzae, pneumococci, meningococci and group B streptococci the organism responsible could be identified in 41 cases (79%) within one hour with specific antisera by means of countercurrent immunoelectrophoresis (CIE). False positive results were not observed in meningitis caused by other organisms, aseptic meningitis, septicemia, etc. In 4 cases the organism could only be identified by CIE since the children had received antibiotics and the culture was negative. Group B meningococci are often missed in CIE. CIE proved to be a valuable tool in diagnostic procedures of bacterial meningitis.