We present the case of a 50-year-old woman with abdominal pain, nausea, loss of appetite, and frequent stools in whom the routine ultrasonographic examination demonstrated a double-reflective, ribbon-like structure in the lumen of the initial segment of the ascending colon, which suggested colon taeniasis. Because the initial parasitologic analysis yielded negative results and application of albendazol did not have any therapeutic effect, the diagnosis was confirmed by barium enema and subsequently by parasitologic examination of proglottids passed in the stool after application of niclosamide. The double-reflective, ribbon-like structure in the lumen of the intestine seems to be specific to the ultrasonographic appearance of intestinal taeniasis. Transcutaneous ultrasonography of the gastrointestinal tract, performed as a screening method before conventional radiologic or endoscopic examination, can point to the ultimate diagnosis of colon taeniasis.