The practice of reprocessing endoscopes and its effectiveness was evaluated in 37 services. Contamination of at least 1 endoscope could be identified in 34 (91.6%) of 37 services. Bacteria, fungi, and/or mycobacteria were isolated from 84.6% (33/39) of the colonoscopes (110–32,000 colony-forming units [CFUs]/mL) and from 80.6% (50/62) of the gastroscopes (100–33,000 CFUs/mL). Not all services followed recommended guidelines. Therefore, patients who underwent gastrointestinal endoscopies were exposed to diverse pathogens.