This study examined daily partner-focused petitionary prayer (PFPP) on relationship communication and quality as well as novel indices of cardiovascular functioning in a sample of 90 adults. PFPP was compared to waitlist and meditation conditions over a 4-week period. Aortic hemodynamics via pulse wave analysis were assessed before and after the intervention. Factorial repeated measures analyses indicated that for those in the prayer condition, there were significant improvements in coronary perfusion, decreased left ventricular work, and increased coronary blood flow. Additionally, the perceived positive aspects of one's relationship improved for those in the prayer condition. Similar changes did not occur in waitlist and meditation conditions. Findings suggest that daily PFPP improves relationship quality and cardiovascular efficiency via improving protective cardiovascular mechanisms. Practical implications are briefly discussed.