REGARDLESS of its size, Meckel's diverticulum may escape detection for long periods of time. It must be considered in every case of gastrointestinal dysfunction of an obscure nature. The diverticulum described in this case report is of interest because of its unusually large diameter and unusual position, as well as its prolonged symptomatic history. Report of a Case An 11 1/2-year-old white girl was referred because of chronic anemia. Interrogation revealed that she had been afflicted with chronic vomiting since birth. During infancy, the attacks of vomiting occurred several times daily. At the age of 6 1/2 months she was studied at another hospital, where roentgenographic studies of the stomach and small intestine failed to demonstrate any abnormality. Thereafter, it was assumed that the vomiting was on a functional rather than a mechanical basis. The frequency of episodes of vomiting gradually decreased; when the patient reached the age of six,