The intrapulmonary renin-angiotensin system via tissue concentration of angiotensin II or bradykinin may have multiple effects on pulmonary pathophysiology. Therefore, it was investigated whether the presence of the D allele of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism or the A allele of angiotensinogen (AGT) promoter polymorphism (-6)A/G are independent risk factors for 30-day survival in acute respiratory distress syndrome (ARDS) patients. In a prospective study, adults (Germans of Caucasian ethnicity) with ARDS (n = 84) were recruited from the current authors' intensive care unit and genotyped for the ACE I/D and the AGT (-6)A/G polymorphisms, as were 200 healthy Caucasian controls. Mortality was increased in the ACE DD genotype compared with the I allele, and the ACE I/D polymorphism was an independent prognostic factor for 30-day survival. Patients with a homozygous DD genotype were at highest risk for death (hazard ratio 5.7; 95% confidence interval 1.7-19.2) compared with the II genotype. In contrast, the AGT (-6)A/G polymorphism was neither associated with an increased risk for development of ARDS nor with outcome. In patients with acute respiratory distress syndrome, the angiotensin-converting enzyme insertion/deletion polymorphism but not the angiotensinogen (-6)A/G promoter polymorphism is an independent risk factor with a pronounced effect on 30-day survival.