Abstract Background A low cerebrospinal fluid (CSF) white-blood cell count (WBC) has been identified as an independent risk factor for adverse outcome in adults with bacterial meningitis. Whereas a low CSF WBC indicates the presence of sepsis with early meningitis in patients with meningococcal infections, the relation between CSF WBC and outcome in patients with pneumococcal meningitis is not understood. Methods We examined the relation between CSF WBC, bacteraemia and sepsis in a prospective cohort study that included 352 episodes of pneumococcal meningitis, confirmed by CSF culture, occurring in patients aged >16 years. Results CSF WBC was recorded in 320 of 352 episodes (91%). Median CSF WBC was 2530 per mm 3 (interquartile range 531–6983 per mm 3 ) and 104 patients (33%) had a CSF WBC