To examine possible sources of Campylobacter pylori and to determine the routes by which it is transmitted to the human stomach, samples of dental plaque and saliva from 71 patients undergoing endoscopy in addition to stomach biopsies were collected and cultured on selective noninhibitory Skirrow medium. A total of 29 (40.8%) of the stomach biopsies yielded C. pylori. None of the saliva samples and only one of the dental plaque samples was found positive for C. pylori, and thus neither saliva nor dental plaque could be implicated as a significant reservoir of this organism.