Although a transient bacteremia may occur in approximately 4% of patients after colonoscopic procedures, clinically significant bacteremia or endocarditis is exceedingly rare. To our knowledge, the case we describe herein is the first reported case of septicemia due to Flavobacterium meningosepticum and Escherichia coli after colonoscopic polypectomy. Our patient was probably immunocompromised and, therefore, predisposed to bacteremia after the procedure, because she was asplenic, diabetic, and receiving long-term steroid therapy for her chronic autoimmune disorders. Several recent reports have suggested that immunocompromised patients are more likely to develop septicemia after endoscopic procedures.