The value of the latex agglutination test in meningitis was assessed. This was positive in 60% cases of Streptococcus pneumoniae, 93% of Haemophilus influenzae type b, and 39% of Neisseria meningitidis infections. We cannot support the view that this test was more valuable than Gram staining in partially treated meningitis and cannot recommend its routine use. It may, however, be valuable if Gram staining does not identify an organism or if it suggests meningococcal infection.