Continuous ambulatory peritoneal dialysis (CAPD) peritonitis is a major complication of peritoneal dialysis (PD) and leads to the discontinuation of PD. Despite its limited pathogenicity, CAPD peritonitis caused by Stenotrophomonas maltophilia (S. maltophilia), an important nosocomial pathogen that is present in nature and is usually associated with plastic indwelling devices. Infection of S. maltophilia is associated with a poor prognosis, including inability to maintain the CAPD catheter, because of its resistance to multiple antibiotics. We report a case of CAPD peritonitis due to S. maltophilia that was treated successfully using oral Trimethoprim-sulfamethoxazole and intraperitoneal Ticarcillin/clavulanate without removing the dialysis catheter.