Endothelin-1 (ET-1), which is produced by vascular endothelial cells, has potent vasoconstrictor and proliferative activity in vascular smooth muscle cells, and therefore has been implicated in regulation of vascular tonus and progression of atherosclerosis. We recently demonstrated that the plasma ET-1 concentration was significantly decreased by aerobic exercise training in healthy young humans and healthy older humans. However, it is unclear whether the production of ET-1 is altered by resistance exercise training. We measured the plasma ET-1 concentration before and after resistance exercise training in healthy young humans. Six healthy young men (26 +/- 1 years old) performed 8 weeks of resistance exercise training (3 days/week). There were no significant differences in body composition, blood pressure, heart rate, and maximal oxygen consumption before and after resistance exercise training. The girths of the arm and thigh significantly increased after resistance exercise training. The maximal muscle powers in the arm and leg increased after resistance exercise training. After resistance exercise training, the plasma concentration of ET-1 significantly decreased. The present study suggested that resistance exercise training, as well as aerobic exercise training, reduces the plasma ET-1 concentration in healthy young humans, and that this reduction in plasma ET-1 concentration may have beneficial effects on the cardiovascular system.