Transient bacteremia during and after endoscopic procedures is a well- documented phenomenon, but complicated bacteremia such as endocarditis in patients at risk is considered to be extremely rare. The recommendations for prophylaxis before endoscopy in patients with valvular heart disease were recently released. We discuss 16 cases of complicated bacteremia that developed after endoscopy (eight cases previously published in the literature and eight cases we encountered). The endoscopic procedures were gastroscopy (five cases), sclerotherapy (six cases), sigmoidoscopy (three cases), and esophageal dilation (two cases). Fourteen patients had underlying disease: valvular heart disease (six patients), cirrhosis of the liver (five patients, one of whom also had a prosthetic knee), valvular heart disease and cirrhosis of the liver (two patients), and gastric carcinoma (one patient). The organisms involved were Streptococcus viridans (six cases), streptococcus group D (three cases), Streptococcus pneumoniae (two cases), Streptococcus microaerophilicus (two cases), Staphylococcus aureus (two cases), and Cardiobacterium hominis (one case). The patients presented with the following infections: endocarditis (12 patients), spontaneous bacterial peritonitis (two patients), septic arthritis (one patient), and brain abscess (one patient). The outcome was good in 15 patients; one patient died. Patients with valvular heart disease, cirrhosis of the liver, ascites, malignancies, or prosthetic joints who undergo endoscopic procedures should be considered for antibiotic prophylaxis.