The properties of three cobalt based hardfacing deposits containing 0?37, 0?56 and 0?82 wt-% of carbon were studied. The results showed that hardness is enhanced with the increase in carbon contents in the case of as deposited condition and tempering treatment. The increasing rate in hardness increases with the increase in tempering temperature and time but declines with the increase in carbon contents in the hardfacing metal. In addition, the wear loss decreases with the increase in carbon contents at room temperature (RT) and 600uC. In comparison, there is a significant increase in the amount of wear of the metals at 600uC to that at RT. Oxidation tests at 600uC for 100 h showed a slight variation in weight loss of cobalt based metals with different carbon contents. It was also found that the carbon content reduces the crack resistance of cobalt based hardfacing deposits.