We report the case of a 71-year-old male with Bacteroides fragilis bactermia and infected aortic aneurysm that went undiagnosed, in part, because routine anaerobic blood cultures were not obtained. Bacteremia caused by anaerobes has been reported to be declining, and recommendations to discontinue routine anaerobic blood cultures have been implemented in some hospitals. To our knowledge, this is the first report of an anaerobic bacteremia and infection that had a delay in diagnosis due to this change in blood-culturing protocol. The potential impact of deleting anaerobic blood cultures from routine protocols is discussed.