RRF has been shown to decline progressively with time on dialysis in both CAPD and hemodialysis. Although RRF is an important determinant of mortality and morbidity in peritoneal dialysis (PD) patients, few studies have addressed therapeutic approaches for preserving RRF after the initiation of dialysis therapy. Blockade of the renin-angiotensin system by ACEI or ARB is a well-established approach for renoprotection in pre-dialysis chronic kidney disease patients. Up to now, only two trials showed that an ACEI, ramipril, and ARB, valsartan , were effective in the preservation of RRF of CAPD patients. However it is important to point out that the evidence cited has limitations. First, the trial only involved patients from one university teaching hospital. Second, transport characteristics, were not assessed before the start of the study. Third, the trial was too small to detect potentially important differences in health care use and survival between groups. Therefore, whether both ACEI and ARB preserve RRF, improve clinical outcomes and decrease health care use and costs should be tested in much longer and larger studies involving multiple sites. In order to confirm these findings, here the investigators will perform prospective, randomized, open-label and multiple center study to address long-term effects of ACEI, ARB and combination of both therapy on RRF in Patients on CAPD.