A close relationship exists between nodular gastritis and Helicobacter pylori infection in children. The pathogenesis and optimal management of nodular gastritis in adults, however, are unclear. This study describes the clinicopathologic features of nodular gastritis in adults and correlates treatment with outcome. Of 97,262 adult patients who underwent endoscopy, 187 (0.19%) were diagnosed with nodular gastritis, 151 (81%) of whom had dyspepsia. Nodular gastritis predominantly affects young women (49 men and 138 women, mean age, 32.6 years). All 134 patients tested for Helicobacter pylori infection were infected, and 65/66 (98%) had inflammation of both the antrum and the corpus. Twenty-five (13%) had associated lesions (peptic ulcers or cancer). Dyspepsia improved after eradication of Helicobacter pylori infection, but did not improve spontaneously. Nodular gastritis in adults is caused by Helicobacter pylori infection and shows a predilection for females and young adults. Helicobacter pylori eradication decreases symptoms and reduces the risk of peptic ulcers and possibly gastric cancer.