This study was designed to examine the role of vascular endothelial growth factor (VEGF) in pulmonary endothelial cell injury by exercise in asthmatics. Post-exercise circulating thrombomodulin (TM) levels were significantly increased in asthmatics. Moreover, the increase in TM levels with exercise was significantly correlated with VEGF level in induced sputum from asthmatics (r = 0.80, p = 0.0007). After inhaled steroid therapy, post-exercise TM levels were significantly decreased, but the increase in TM levels with exercise was also correlated with VEGF level (r = 0.60, p = 0.01). Thus, pulmonary endothelial cells stimulated by VEGF in asthmatic airways may be sensitive to exercise challenge.