Major role of Helicobacter pylori in the pathogenesis of gastro duodenal diseases such as gastritis, ulcers, gastric adenocarcinoma and lymphoma is well established today. Several factors are involved in virulence. Presence of Cag gene is responsible for chronic gastritis and to identify strains to be treated. The aim of this study was to determine presence of Cag gene and risk factors associated. This study included 79 adult ambulatory or hospitalized patients with clinical symptoms justifying upper endoscopy at the University Hospital of Cocody for the period from May to September 2009. Clinical and socio-demographic information was collected from a plug investigation. Detection of Cag gene was made by PCR method. The average age was 52.31 years with a minimum of 20 years and a maximum of 86 years. The most represented age group was above 50 years. Prevalence of Cag gene was investigated in 20 patients was 65% (13/20) with a male predominance of 53.8%. Unemployed accounted for 38.5% of holders of Cag gene and epigastralgia, the first such pattern endoscopy 38.5%. 46.2% of the holders of Cag gene had a family history of ulcer syndrome. Age, sex and family environment are risk factors associated with H. pylori infection in Abidjan.