Sarcina organisms were first observed in and recorded from the stomach contents of a patient suffering from vomiting by John Goodsir in 1842. Since that time, their fine structure, phylogenetic classification, and biochemical characteristics have been described. Although numerous cases of fatal disease have been attributed to this organism in the veterinary literature, only a few human cases have been documented. As a result, whether this organism causes disease in humans has not been definitively established. We report the clinicopathologic findings in a series of 5 patients with Sarcina-like organisms identified in upper gastrointestinal endoscopic biopsies with molecular confirmation. Our findings have shown that the organism is most commonly found in patients with a history of gastric outlet obstruction or delayed gastric emptying. Although many of the patients do not demonstrate direct mucosal injury from the organism, the presence of a concurrent gastric ulcer puts the patient at increased risk for complications such as emphysematous gastritis or perforation. The finding of Sarcina organisms should prompt further investigation for functional causes of gastric outlet obstruction and delayed gastric emptying, such as occult malignancy.