The authors depict 13 cases of CNS injuries in the form of meningities, meningoencephalitis and encephalitis in adults, provoked by Haemophilus influenzae. Provide the clinical, laboratory and instrumental data obtained during examination of the patients in the acute disease stage and during follow-up studies lasting up to 5 years. Rare strains of Haemophilus influenzae, serotypes "c" and "d", were detected in the CSF. Concomitant virus infection was confirmed in seven patients. It is desirable that chloramphenicol, erythromycin or ampicillin be used in such cases. Patients who suffered influenzal meningitis should undergo follow-up studies.