Objectives: This project intends to evaluate, up to 6 months, the role of autologous mesenchymal stem cells in improvement of peritoneal membrane function in peritoneal dialysis patients who have ultrafiltartion failure. Design: In this study, 10 male and female subjects who are on peritoneal dialysis for at least two years and have ultrafiltration failure with age range of 18 to 70 years will be enrolled. Setting and conduct, participants and intervention: Patients will be selected from peritoneal dialysis patients attending the peritoneal dialysis ward of Dr. Shariati hospital. The main inclusion criteria is to be on peritoneal dialysis for at least last two years and having Ultrafiltration failure. After obtaining the consent form, a small sample of fat tissue will be obtained by a general surgeon under sterilized condition frompatients and then in the specialized lab, the mesenchymal stem cells will be separated and cultured to reach appropriate numbers (106/kg). The cells will be injected through peripheral vein in hospital setting. Patients will be followed-up (clinically and laboratory) at baseline and at week 3, week 6, month 3, month 4 and month 6. The clinical assessment and peritoneal function tests will be performed in each visit. Outcome measures: The main outcome measures that periodically will be assessed include: D/P cr, D/P urea, D0/D glucose, PET, KT/V urea, Glomerular filtration rate (GFR)