The threefold purpose of this report is to describe the epidemiology of acute flaccid paralysis (AFP), to determine the impact of the National Immunization Days (NID), and evaluate the quality of active surveillance in the Central African Republic (CAR) and Chad. The data in this study was obtained from the Enterovirus Division of the Pastear Institute in Bangui (National WHO Inter-country Reference Laboratory for the CAR and Chad and Regional Poliovirus Reference Laboratory in Africa). An increase in the number of AFP cases was observed in the CAR between 1995 and 2000 and in Chad between 1997 and 2000, mainly as a result of enhancement of the surveillance system. The goals set by the WHO in terms of the proportion of AFP cases with 2 specimens collected within 14 days of onset of paralysis and the number of cases with 60-day follow-up have not been reached in either country. The presence of 2 strains of wild poliovirus (types 1 and 3) and several genotypes (West African 13 and West African 7 for type 1 and Central African and Nigeria-P3 for type 3) not only show that Central Africa is still a significant reservoir for poliovirus transmission but also raise serious doubts about the quality of the NID organized over the last 3 years. The priority of the next NID round must be to reach unimmunized children who have been missed by routine immunization coverage.