The endoscopic examination of a 66-year-old male patient revealed a protruding lesion close to a reddish IIc area in the antrum of the stomach. The protruding lesion and reddish area were resected completely with endoscopic mucosal resection using an insulation-tip diathermic knife (IT-EMR). Histological examination of the protruding lesion revealed proliferation of fibroblasts and infiltration of inflammatory cells, and it was diagnosed as an inflammatory fibroid polyp (IFP). Adenocarcinoma in the IIc area was present adjacent to the IFP. This may be the first report of gastric cancer concomitant with gastric IFP treated by endoscopic mucosal resection.