Gastroduodenal Crohn's Disease (CD), which is uncommon in adults, involves the gastric antrum and proximal duodenum in most cases, and results in epigastric pain, weight loss, and gastric outlet obstruction, raising initial suspicion that it may be peptic ulcer disease or a malignancy. On upper endoscopy, aphthous ulcers are typical in the early stages but linear or stellate ulcers with a cobblestone appearance and luminal narrowing can be found in advanced diseases. Multiple mucosal biopsies are helpful for diagnosis despite the fact that granulomas are seen in less than one third of all cases. Gastroduodenal CD requires oral sulfasalazine therapy or systemic corticosteroid therapy in advanced cases. A case of gastroduodenal CD in a 37-year-old man admitted with epigastric pain, anorexia, vomiting and weight loss is herein reported. Malignancy was suspected as a result of the patient's clinical manifestations and endoscopic findings. An endoscopic biopsy revealed an active inflammation in the mucosa and lamina propria. The patient's condition improved with oral sulfasalazine and prednisolone therapy.