Objective: To describe the prevalence of Helicobacter pylori (HP) in children and adolescents, and to assess its association with lesions in the esophagus, stomach, and duodenum according to the patient’s life cycle. Methodsː A cross-sectional analytical study with children and adolescents referred to a gastroenterology service and underwent esophagogastroduodenoscopy at a hospital in Vitória, Espírito Santo, Brazil, from 2001 to 2013. Variables analyzed were the following: sex, age, macro and microscopic alterations and severity of infestation. The Chi-square and Fisher's exact tests and adjusted residue analysis were used (α = 5%). Resultsː the prevalence of infection was 24.4%. Esophagitis (29.4%) and gastritis (34.1%) were associated with HP. The life cycle was associated with esophagitis and duodenitis. Infection was associated with life cycle: infants (0.8%), preschool children (10.5%), school-aged children (16.5%), and adolescents (72.2%). The residues showed a strong association between HP and gastritis, and no association between the school-aged and esophagitis. Adolescents were the major contributors to the association between life cycle and infection, and life cycle and lesion. Conclusionsː Infection with HP was associated with esophagitis and gastritis and was higher among adolescents, who had a marked tendency to develop gastritis and a milder tendency to develop esophagitis. The tendency of developing infection and gastritis was not present in the other life cycles. Public policies focusing on promotion and protecting health, especially in vulnerable population groups, are needed.