Background : The stiffened arteries in ankylosing spondylitis (AS) may be the cause of the higher cardiovascular burden. P-wave dispersion (PWD), measured from surface electrocardiogram (ECG) leads, has been demonstrated as a reliable indicator of the onset of atrial fibrillation (AF). Objective: We aim to examine PWD in AS and establish how it relates to aortic elasticity. Patients and methods: A case-control study was conducted on 136 participants. They were classified into two groups; control (Group I) 46 volunteers, AS (Group II) 90 cases were subjected to aortic elasticity parameters and assessed by m-mode, stiffness index (SI), D (Distinsibility) and tissue doppler imaging (TDI) on aortic systolic velocity (AO_S). PWD duration by surface (ECG); lipid profile and blood pressure were assessed. Results: SI was higher in AS than in the control [25.62±5.68 vs. 11.18±2.19, respectively (P<0.001)]. AO_S was lower in AS than in the control [12.3±2.2 vs. 16.1±0.96, respectively (P<0.001)]. PWD was higher in AS group than in the control. PWD and SI correlated positively (r= 0.831, P<0.001). Conclusion: Prolonged PWD was correlated with impaired aortic elasticity indexes. A higher risk of having AF may result from the increased PWD duration.