To evaluate the effect of influenza vaccination on the coronary events in patients with confirmed coronary artery disease (CAD). Randomized, double-blind, placebo controlled study. We included 658 optimally treated CAD patients; 477 men, mean age 59.9±10.3 years. Three hundred and twenty-five patients received the influenza vaccine, and 333 patients placebo. Median follow-up was 298 (interquartile range 263–317) days. Primary endpoint was the cardiovascular death. Its estimated 12-month cumulative event rate was 0.63% in the vaccine vs. 0.76% in controls (HR 1.06 95% CI: 0.15–7.56, P = 0.95). There were two secondary composite endpoints: (i) the MACE (cardiovascular death, myocardial infarction, coronary revascularization) tended to occur less frequently in the vaccine group vs. placebo with the event rate 3.00 and 5.87%, respectively (HR 0.54;95% CI: 0.24–1.21, P = 0.13). (ii) Coronary ischaemic event (MACE or hospitalization for myocardial ischaemia) estimated 12-month event rate was significantly lower in the vaccine group 6.02 vs. 9.97% in controls (HR 0.54; 95% CI: 0.29–0.99, P = 0.047). In optimally treated CAD patients influenza vaccination improves the clinical course of CAD and reduces the frequency of coronary ischaemic events. Large-scale studies are warranted to evaluate the effect of influenza vaccination on cardiovascular mortality. (ClinicalTrials.gov: NCT 00371098).