This paper reported the implementation of cable stress monitoring for a cable stayed bridge. A Structural Health Monitoring (SHM) system was installed to a cable stayed bridge with main span of 480m, upon its completion in December 2006. Electro-Magnetic (EM) sensors were used to monitor the stress and temperature of the cables, in addition to displacement and strain. Data shows that changes in cable temperature lag behind ambient air temperature. Stresses of longest cables are linearly related to temperature. However, the stresses of the shortest cables near the pylon were affected by combination of both temperature and other factors. Small change in average cable stresses before and after typhoon indicates a stable performance of the entire structural system.