Glanzmann's thrombasthenia (GT) is a rare bleeding disorder inherited in an autosomal recessive manner. The pathogenesis of GT mainly involves structural abnormalities and dysfunction of platelet membrane glycoprotein IIb/IIIa (integrin aIIbb3). The most common symptoms of GT are various types of bleeding, including recurrent nasal bleeding, mucocutaneous bleeding, unremitting bleeding after injury or operation, and menorrhea in women. Such hemorrhage may be fatal in some patients. GT with spontaneous upper gastrointestinal bleeding is relatively rare. In the present report, we describe a middle-aged man who was hospitalized with spontaneous upper gastrointestinal bleeding. His main symptom was recurrent chronic and intermittent melena. Gastroscopy revealed oozing of blood in the gastric antrum wall. However, no obvious lesions such as erosion or ulceration were found. Upon further inspection, we found that the patient's platelet aggregation was poor, and flow cytometry assay revealed low expression of platelet membrane integrin aIIbb3. The patient was eventually diagnosed with GT and exhibited clinical improvement after active treatment.