OBJECTIVE Collagenous gastritis is a rare entity, characterized by the deposition of a subepithelial collagen band with an inflammatory infiltrate in the mucosa. This report describes the first case of collagenous gastritis occurring in a young Chinese woman and reviews the literatures. METHODS The patient underwent the gastroscopy screening, and the biopsy specimens were treated with HE staining, Masson staining, Congo red staining and Warthin-Starry staining.Patients' clinical data was discussed and followed up. RESULTS A twenty-year-old girl had intermittent epigastric pain for 4 years, abdominal distention, hiccup and weight loss for two months. The gastric endoscopy revealed diffuse white nodular appearance of the mucosa in angular incisura and antrum. Pathologic examination of the gastric biopsies from the antrum and angular showed a subepithelial collagen deposition with moderate infiltrates of lymph plasma cells and eosinophils of the lamina propria. The collagen band measured up to 120.3 µm (mean 43.8 µm). Prednisone 20 mg/d for 4 weeks led to clinical remission and weight gain. CONCLUSIONS There are about 40 cases in literatures to date, and the cause and pathogenesis of collagenous gastritis remain unknown. According to the clinical and pathological characteristics, the patient in this article is the subtype of collagenous gastritis that occurring in children and young adults. Specific therapy has not been established, the gluten-free diet and glucocorticosteroid may be helpful to relieve symptoms in collagenous gastritis patients.