Cardiovascular disorders (CVD) are associated with acute and posttraumatic stress responses, yet biological processes underlying this association are poorly understood. This study examined whether renin-angiotensin-aldosterone system activity, as indicated by a functional single nucleotide polymorphism (SNP) in the angiotensin converting enzyme (ACE) gene, is associated with both CVD and acute stress related to the September 11, 2001 (9/11) terrorist attacks. European-American respondents (N = 527) from a nationally representative longitudinal study of coping following 9/11 provided saliva for genotyping. Respondents had completed health surveys before 9/11 and annually for 3 years after, and acute stress assessments 9 to 23 days after 9/11. Respondents with rs4291 AA or TT genotypes reported high acute stress twice as often as those with the AT genotype. Individuals with the TT genotype were 43% more likely to report increased physician-diagnosed CVD over 3 years following 9/11, when the following variables were included in the model: (a) pre-9/11 CVD, mental health, and non-CVD ailments; (b) cardiac risk factors; (c) ongoing endocrine disorders; and (d) significant demographics. The ACE rs4291 TT genotype, which has been associated with HPA axis hyperactivity and higher levels of serum angiotensin converting enzyme (ACE), predicted acute stress response and reports of physician-diagnosed CVD in a national sample following collective stress. ACE gene function may be associated with both mental and physical health disorders following collective stress.