A male patient aged 41 years had dialysis pericarditis with massive pericardial effusion in his 6-year on continuous ambulatory peritoneal dialysis (CAPD). Intensive hemodialysis failed to resolve the pericardial effusion. Pericardiocentesis via a subxiphoid approach was performed with placement of a pigtail catheter for drainage. A communication between peritoneal and pericardial cavities occurred, resulting in the leakage of the peritoneal dialysate into pericardial sac which was confirmed by a 99mTc radionuclide scan. The fistula healed after removal of the catheter and discontinuation of CAPD. We suggest that pericardiocentesis via a subxiphoid approach for pericardial effusion should be cautiously exercised in CAPD cases for fear of peritoneopericardial fistula.