['To investigate the effects of angiotensin converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) and other anti-hypertensive agents on recombinant human erythropoietin (rHuEPO) in chronic renal failure (CRF) patients.', "The present study was conducted at the Nephrology Department, Khan Research Laboratories Hospital and Quaid-i-Azam University, Islamabad, Pakistan during March 2004 to February 2005. One hundred patients, 55 males and 45 females (age range 13-78 years) were divided into 2 groups. Group-I patients received rHuEPO and ACE inhibitors/ARBs while Group-II patients received rHuEPO with other antihypertensives such as calcium channel blockers or beta-adrenergic receptor blockers. Monthly increment in hematocrit (HCT%) was monitored in both groups for 4 continuous months. One-way ANOVA on Dunn's, univariate and multivariate analyses were carried out to determine any significant improvement in erythropoiesis between the 2 treatment groups.", 'Monthly increase in HCT% was significantly greater in the group that was treated with rHuEPO and antihypertensives other than ACE inhibitors/ARBs compared with that treated with ACE inhibitors/ARBs, an effect observed even at a higher dose of rHuEPO, and the patients were iron replete.'] Do angiotensin converting enzyme inhibitors impair recombinant human erythropoietin induced erythropoiesis in patients with chronic renal failure?