A 51-year-old woman with epigastralgia was admitted to our department on November 30, 1990. X-ray examination using barium and endoscopy revealed a submucosal tumor with a smooth surface and regular margins in the cardiac part of the stomach. Endoscopic ultrasonography visualized the tumor as a diffuse echo area with unclear borders in the submucosa; the echo level was slightly lower than that for the liver. An oval region measuring 5×7 mm appeared inside the tumor, and there were round, low-echo areas representing lymphnodes measuring about 5 mm outside the gastric wall. These findings were not sufficient for qualitative diagnosis of the gastric submucosal tumor. Tumorectomy performed in the department of surgery at our hospital on January 17, 1991 revealed that an Anisakis worm was present in the submucosa, and that the abscess was formed around the worm, accompanied by severe infiltration of eosinophils. The eosinophilic abscess was enclosed by a round granuloma measuring 5-7 mm, which was further surrounded by severe edema. The lymphnode swelling was reactive and accompanied by eosinophilic infiltration. The endoscopic ultrasonography study showed that the granuloma and surrounding edema were due to an Anisakis worm. There has been no report documenting endscopic ultrasonographic findings of gastric submucosal tumor due to an Anisakis granuloma. This paper reports a valuable case of this condition.