Objective: To determine the incidence of bacteremia, as detected by routine methods for bacterial culture of blood samples, following routine endoscopic biopsy of the stomach and duodenum in healthy research dogs and to determine whether treatment with omeprazole administration affected the incidence of bacteremia. Animals: 8 healthy purpose-bred research dogs. Procedures: All dogs underwent gastroduodenoscopy with biopsy at 4 points: twice prior to treatment with omeprazole, once following 15 days of omeprazole treatment (20 mg, PO, q 12 h), and once 14 days after treatment ceased. Dogs had a mean ± SD body weight of 18.6 ± 2.0 kg. Blood samples were aseptically obtained at 3 points during each procedure (before, immediately following, and 24 hours after endoscopy), and routine aerobic and anaerobic bacterial culture of blood was performed. Results: 96 cultures were attempted for each culture method, yielding positive results of aerobic culture for 2 dogs at separate time points and no positive results of anaerobic culture. Conclusions and Clinical Relevance: Routine gastrointestinal endoscopy with biopsy in healthy dogs did not result in a detectable bacteremia in most dogs. Treatment with the gastric acid–suppressing medication omeprazole did not affect the incidence of bacteremia as detected via standard techniques.