Stercoral colitis is a colonic inflammation caused by fecal impaction. It is now more commonly discussed in the literature due to its clinical significance, which has gained recognition in recent years. Delayed diagnosis may result in complications such as sepsis and perforation, which have a high mortality rate. Reporting incidentally detected stercoral colitis on FDG PET/CT can help prevent mortality and morbidity by enabling early diagnosis and treatment. In this case, we report on a patient with gastric cancer who was identified with stercoral colitis using FDG PET/CT data.