The present study has been undertaken to assess the electrical activity of right tibialis anterior, right gastrocnemius, right rectus femoris, right biceps femoris and right paralumbarvertebral muscles quantitatively by EMC while standing erect on the height of 0cm, 3cm, 5cm and 7cm heels. The inclinations of the heels were 0, 6, 11, 17 degrees, respectively. Fourty young women ranging from 18 to 24 of age were examined. Electrical activity of various muscle while standing erect on the height of various heels were compared with that of 0cm heel. The results obtained were as follows : 1. Electrical activity of the tibialis anterior increased significantly as the height of heels became higher ; which was thought to be due to the effort to counteract the instability standing with high heels. 2. There was a significant increase in electrical activity of the gastrocnemius as the height of heels increased. It might be due to compensatory activity against shifting of the center of gravity forward. 3. There was a significant increase in electrical activity of the rectus femoris and biceps femoris at the height of 3cm, 5cm arid 7cm heels ; which seemed to be due to the effort to stabilize the knee joint. 4. Electrical activity of the paralumbarvertebral muscles increased significantly at the height of 5cm and 7 cm heels ; which was considered to be due to the effort to prevent forward imbalance. From These results, it may be concluded that electrical activities of various postural muscles increase significantly while standing erect on the height of 3cm, 5cm and 7cm heels to counteract an instability of their posture and compensate the forward shifting tendency of the center of gravity.