An interrelation between heart rate and arterial stiffness is established. However, the relationship between cardiac pacing mode and the stiffness of arterial vessels is not. This study investigated arterial stiffness parameters such as carotid-femoral pulse wave velocity (cfPWV) and aortic augmentation index (AIx) in pacemaker subjects (n=46) paced via atrial (Ap), ventricular (Vp), or atrial ventricular (ApVp) modes at 60, 70, 80, 90 and 100 bpm in the supine position. At each heart rate, brachial blood pressure was measured, the central aortic pressure waveform derived using a validated transfer function applied to brachial cuff waveforms (SphygmoCor XCEL), and cfPWV measured using simultaneous acquisition of the carotid (tonometer) and femoral (thigh cuff) pulse. Aortic and brachial systolic, diastolic, and mean pressure did not differ between pacing modes. However, AIx was lower with ApVp (24±9 %) and Vp (19±11 %) pacing than Ap pacing (34±10 %, p<0.001), with Vp being lower than ApVp (p<0.01). Ejection duration followed the exact pattern of AIx. Aortic pulse pressure was also lower with ApVp (37±9 mmHg) and Vp (36±11 mmHg) pacing than Ap pacing (42±12 mmHg, p<0.01). However, cfPWV was greater with ApVp pacing (10.6±1.9 m/s, p<0.05) and Vp pacing (11.0±2.1 m/s, p<0.01) than Ap pacing (9.8±1.7 m/s). This study showed differences in vascular stiffness with cardiac pacing modes. Further research is required to investigate the opposing changes in AIx and cfPWV and to determine if pacing mode drives differences in arterial stiffness or differences are characteristic of the subjects assigned to different pacing modes.