BACKGROUND Antibiotic prophylaxis has been recommended for selected patients undergoing esophageal stricture dilation because of a reported high rate of bacteremia. The aim of this study was to determine the rate of bacteremia after esophageal dilatation in a large series and the source of the organisms recovered. METHODS Blood cultures and oral temperatures were obtained before esophageal dilation and at 5 and 30 minutes after dilation. Dilators were cultured immediately before dilation. Procedural data collected included type of dilation, number of passes, and presence of malignancy. RESULTS Of 100 procedures in 86 patients undergoing esophageal dilation, 22 (22%) were associated with a positive post-dilation blood culture. Bacteremia was more frequent with dilation of malignant strictures compared with benign strictures (9 of 17 [52.9%] vs. 13 of 83 [15.7%], respectively, p = 0.002) and with passage of multiple dilators compared with passage of a single dilator (16 of 46 [34.8%] versus 6 of 54 [11.1%], respectively, p = 0.007). Bacterial isolates from 22 positive blood cultures matched those from a dilator in only one episode (4.5%). CONCLUSIONS The rate of bacteremia after esophageal dilation is 22% and is associated with dilation of malignant strictures or passage of multiple dilators. Organisms cultured from the blood are not transmitted from the dilator.