In this report, we describe a patient with acute terminal ileitis due to Streptococcus pneumoniae, review 3 previously reported cases of isolated enteritis due to S. pneumoniae, and summarize the English-language literature on primary and secondary pneumococcal gastrointestinal diseases. Various theories have been advanced to explain the pathogenesis of this rare and potentially life-threatening form of pneumococcal infection, but the mechanism by which S. pneumoniae causes gastrointestinal disease is still unknown.