Gastric syphilis had become an uncommon disease, with only 24 cases reported in the English-language literature over the last two decades. However, it may be becoming more frequent. During the last 4 years, seven patients with gastric syphilis have been diagnosed at our institution. The most common presenting symptoms were abdominal pain, nausea, and vomiting with signs of syphilis present in five patients (71%). After radiographic and/or endoscopic evaluation, the initial diagnosis was considered to be cancer in four patients and nonspecific gastritis in three. The syphilis diagnosis was established by identification of spirochetes on mucosal biopsy in six patients. Although these cases appear typical for gastric syphilis, the diagnosis was usually not considered at first. However, gastric syphilis should be considered in patients at risk for sexually transmitted disease who complain of nausea, vomiting, and abdominal pain and in whom unusual gastric lesions or presumed peptic ulcers resistant to standard therapy are found. © 1994 Raven Press, Ltd., New York.