Idiopathic granulomatous gastritis (IGG) is a diagnosis made only by excluding other causes of granulomatous gastritis, such as infection, foreign bodies, and systemic granulomatous diseases. Recently, several investigators have questioned the existence of IGG. We reviewed the slides and clinical data of all cases of granulomatous gastritis seen at the Cleveland Clinic between 1975 and 1994. In addition to routine hematoxylin and eosin stains, slides from all cases were stained with Ziehl-Neelsen, Gomori's methenamine silver, and Giemsa stains. Clinical information and follow-up were available for 42 patients. The clinicopathologic diagnoses of the 42 patients with granulomatous gastritis were as follows: Crohn's disease (n = 23), three of whom had concomitant chronic active gastritis with Helicobacter pylori infection; sarcoidosis (n = 9), four of whom had concomitant chronic active gastritis with H. pylori infection; chronic active gastritis with H. pylori infection and no other systemic illness (n = 2); distal esophageal adenocarcinoma and chronic active gastritis (n = 2); mucosa-associated lymphoid tissue (MALT) lymphoma with chronic active gastritis and presumed H. pylori infection (n = 2); peptic ulcer complications (n = 2); hypertrophic gastropathy with chronic active gastritis (n = 1); and possible Crohn's disease (n = 1). We conclude that (a) in most cases of granulomatous gastritis, a diagnosis of Crohn's disease or sarcoidosis could be established; (b) the background inflammatory pattern was helpful in suggesting a diagnostic category for granulomatous gastritis; (c) granulomatous gastritis is not associated with H. pylori per se; however, if known cases of Crohn's disease and sarcoidosis are excluded, an association between H. pylori and granulomatous gastritis cannot be ruled out; and (d) IGG, if it exists, is extremely rare.