Background: Post-neonatal tetanus is an important problem. Prevention of tetanus in Nigeria is via immunization with three doses of Diphtheria-Pertussis-Tetanus (DPT)/Pentavalent vaccine at 6, 10 and 14 weeks. The anti-tetanus antibody levels of these children are not known after they had received DPT3/Pentavalent vaccines. Aim: This work was to determine the anti-tetanus antibody (IgG) response in Nigerian children aged six months to five years who had received three doses of DPT vaccine in early infancy. Methods: Children aged six months to five years who were attended to in the University of Calabar Teaching Hospital for acute illnesses were recruited. Their anti-tetanus IgG levels were measured using Enzyme Linked Immunosorbent Assay (ELISA). The optimal cut-off level of ≥0.