In a developing country like Nigeria, the unusual emergence of Haemophilus influenzae type b, resistant to cost-effective antimicrobials, is of serious concern. We report three cases of H. influenzae type b meningitis in young Nigerian children in whom clinical and bacteriological features of resistance to chloramphenicol were identified. One of the cases had concomitant resistance to ampicillin (multiple-drug resistance). Significant anaemia was an associated feature in two cases, one of whom had a recent measles infection. All three cases were malnourished. The possible mechanisms of antimicrobial resistance in H. influenzae infections are highlighted while the need for periodic surveillance of antibiotic resistance profiles in resource-poor countries is emphasized. The potential value of prophylactic measures like H. influenzae type b conjugate immunization is discussed.