In this study, 20 broilers were used to examine the effect of high-voltage electrical stimulation (HVES) on meat quality and the microstructure of the pectoralis muscle. After slaughter, carcasses were randomly distributed into 2 treatment groups (n = 10). In the first group, carcasses were electrically stimulated (500 V, 100 Hz) for 60 s. Carcasses in the second group (nonelectrical stimulation) were used as a control. Meat quality was evaluated by the rate of pH, water-holding capacity, cooking loss, color (L*, a*, b*), shear force, and sarcomere length. As a result, HVES increased the rate of muscle pH decline (P < 0.001). High-voltage electrical stimulation had no effect on water-holding capacity and cooking loss values. Only L* (lightness) values were improved during the storage time (P < 0.01). Tenderness (P < 0.001) and sarcomere length (P < 0.05) values were significantly increased at 2 and 5 d postmortem. In addition, microstructure examination demonstrated that the stimulated muscles had longer sarcomeres; however, the A-, I-, and Z-bands and the mitochondrial membrane structure were intact in HVES and nonelectrically stimulated carcasses. The results showed that HVES is a useful method for improving the tenderness of broiler breast meat.