Calcific uremic arteriolopathy (or calciphylaxis) is a severe complication of renal failure characterized by subcutaneous calcification of the small arteries and tissue necrosis. We describe the case of a woman receiving continuous cycling peritoneal dialysis with calciphylaxis involving upper and lower extremities. After intolerance of intravenous sodium thiosulfate and limited intravenous access options, we administered sodium thiosulfate intraperitoneally and quantitated the amount of extra calcium removed. Intraperitoneal administration of sodium thiosulfate was well tolerated and led to removal of extra calcium with peritoneal dialysis.