We present a 1-year-old boy who was asymptomatic and brought to the emergency room on suspicion of his having swallowed a pin. Confirmation of ingestion of the pin and its passage through the gut was achieved with abdominal radiography. The pin, which was followed with serial abdominal radiographs, was expected to leave the gastrointestinal tract, but was fixed to the right lower quadrant. When the pin had not passed after 10 days, and with increasing concern about the likelihood of perforation, ultrasonography was used to locate its exact position and allow surgical removal. Only a few cases involving the use of ultrasonography to reveal the exact location of an ingested foreign body prior to surgery have been reported in the literature. This case presents an impressive example of the use of ultrasonography to reveal the intra-appendiceal location of an ingested foreign body, and to facilitate its surgical removal.