We have used magnetic resonance imaging with cine velocity mapping to measure flow wave velocity in the thoracic aorta of 20 healthy volunteers of different ages. We have also studied the relationship between propagation of flow wave velocity and regional aortic compliance. Aortic flow velocity increased linearly with age (r = 0.87), and there was a significant difference between the youngest decade [age 10-19, mean velocity 4.3 +/- 0.7 (SD) m/s] and the oldest decade studied (age 50-59, mean velocity 7.2 +/- 0.2 m/s). Flow wave velocity (m/s) was negatively correlated with ascending aortic compliance (microliter/mmHg) (r = -0.75). Magnetic resonance imaging is a noninvasive method for measurement of aortic flow wave velocity that is an important parameter in assessing arterial wall mechanics and blood flow dynamic.