The Epstein-Barr virus (EBV) has been reported to be detectable in about 10% of gastric carcinomas. We performed a comparative study of endosonographic findings of EBV-positive and -negative early gastric carcinomas. Epstein-Barr virus was detected in 11.8% (four of 34) of endosonographically observed early gastric carcinoma lesions. Endoscopic ultrasonography (EUS) revealed a hypoechoic mass in the third layer, which reflected submucosal nodules, in 75% (three of four) of EBV-associated lesions. Endoscopically, in 66.7% (two of three) of EBV-associated carcinomas, the depressed lesion was surrounded by a raised margin covered with normal mucosa and was similar to a submucosal tumour (P < 0.05). Histologically, all three cases of EBV-associated lesions with submucosal tumour invasion had submucosal nodules of carcinoma with lymphoid stroma and 75% (three of four) were located in the gastric body. The ratio of maximal thickness to width of EBV-associated lesions was significantly larger than that of EBV-negative lesions, and this tendency was marked in lesions with submucosal tumour invasion (P < 0.05). This study indicated that EUS and endoscopy are of great use for the determination of EBV association with early gastric carcinoma.