The prevalence of antibodies to CagA protein was evaluated in 174 Helicobacter pylori-positive. subjects: 110 patients submitted to upper gastrointestinal endoscopy and 64 male blood donors. The patients were from different regions of Nigeria: Jos, North, Benue,West and East and the blood donors were from Jos. Sera were assayed for anti-CagA antibodies using Helicobacter p120, CagA ELISA (Viva Diagnostika, Hürth, Germany). Anti-CagA antibodies were detected in 104 (94.5%) patients and in 61 (95.3%) blood donors (P=1.0). Patients from the Benue region presented a lower frequency of anti-CagA antibodies than patients from the other regions (P=0.0004). When the subjects were stratified by age, a significant increase in IgG concentration was observed among the men (P=0.03) but not among the women (P=0.57) or among the blood donors (P=0.83). In conclusion, similarly toAsian countries, CagA-positive H. pylori infection is highly frequent in Nigeria.