OBJECTIVES: To compare the short- and long-term effects of high intensity interval training (HIIT) with usual care moderate intensity continuous training (MICT) on systemic vascular function and stiffness in patients with coronary artery disease undergoing a cardiac rehabilitation program. DESIGN: Randomized controlled trial. METHODS: Fifty-four patients (age=63±8years, 93%male) were randomised to complete 3 sessions/week (2 supervised, 1 home-based) of either 1) 4x4-min HIIT or 2) 40-min MICT, for 4-weeks. Patients then continued 3 unsupervised home-based sessions/week of their allocated training for 11-months. Brachial artery flow-mediated dilation, pulse wave velocity, and blood pressure were measured at baseline, 4-weeks, 3-months, 6-months, and 12-months. Data were analysed using linear mixed modelling and are presented as mean change from baseline (95% CI). RESULTS: HIIT showed a greater improvement in flow-mediated dilation compared to MICT after 4-weeks [1.5%(0.9,2.1) vs 0.1% (-0.5,0.8); p=0.004) but not 12-months [1.2%(-0.2, 2.5) vs 0.4%(-0.8, 1.7); p=0.153). There were no short- or long-term group differences for changes in pulse wave velocity, peripheral or central blood pressure between HIIT and MICT after 4-weeks, or over 12-months. CONCLUSIONS: A 4-week HIIT program was superior to MICT for improving vascular function, but not arterial stiffness or blood pressure. Over 12-months, changes in vascular function, blood pressure and arterial stiffness were similar for HIIT and MICT.