Background & Objective: As renin-angiotensin system (RAS) activity could affect the severity of oxidative stress and inflammatory markers the effect of enalapril and losartan on these markers in renal transplant recipients (RTRs) with RAS polymorphisms was assessed.

 Methods: After determination of RAS genotypes including angiotensin converting enzyme (ACE I/D), Angiotensinogen (AGT M235T) and angiotensin II type 1 receptor (ATR1 A1166C) by PCR, seventy-six RTRs recruited to four groups randomly: first group (17 patients) and second group (24 patients) were treated with E (E⁺: 10mg/daily) and L (L⁺: 50 mg/daily) alone, respectively. The third group (17 patients as positive control) received E+L (E⁺L⁺: 10mg/daily + 50 mg/daily) and the 4^th group (18 patients as negative control) received no medication (E^-L^-). Hs-CRP and total anti-oxidant (TA) as inflammatory and anti-oxidative markers were measured after 2 months. After 2 weeks as washout period, E group changed to L and vice versa as a cross-over design. They were followed for another 8 weeks and hs-CRP and TA were retested.

 Results: Following up the patients (after 2, 4 months of treatment) in treated groups revealed that hs-CRP and TA levels were significantly decreased and increased (consequently) in E⁺L⁺, L⁺, E⁺ groups (P<0.05). On analyzing the relationship between RAS polymorphisms with baseline hs-CRP and TA levels, CC genotype of ATR1 had lower hs-CRP levels (P=0.04). But none of the RAS polymorphisms could predict the anti-oxidative and anti-inflammatory response rate to the drugs (P>0.05).

 Conclusion: E and/or L reduce hs-CRP and increase TA regardless of the RAS genotypes.