We report a case of a chronic infiltrate of the intestinal wall of the transverse colon by the eggs of Enterobius vermicularis in a man who had immigrated to Taiwan from mainland China 50 years ago. During surgery for suspected transverse colon carcinoma, histologic examination of the tumor mass revealed eggs of E. vermicularis embedded in granulation tissue in the submucosa of the transverse colon. Results of a stool examination were negative for eggs but strongly positive for occult blood. The mass in the transverse colon was completely removed during surgery. At the present time, the patient remains asymptomatic.