Staphylococcus aureus (S. aureus) is occasionally a normal inhabitant of the gastrointestinal tract, and rarely considered a cause of enterocolitis. Methicillin-resistant Staphylococcal enterocolitis may cause persistent diarrhea leading to severe complications and even death, without appropriate treatment. Lymphocytic colitis (LC), a subtype of microscopic colitis, is a relatively common cause of chronic watery diarrhea. We report the case of a 73-year-old woman with profuse watery diarrhea caused by methicillin-resistant S. aureus. Soon after treatment of her enterocolitis with vancomycin the patient`s general condition and symptoms improved, although the diarrhea persisted. Through colonoscopic biopsy and immunohistochemical staining, overt LC was diagnosed, and prompt therapy with budesonide was initiated. (Intest Res 2011;9:139-143)