Abstract: In This work, the water content is determined in muscle, liver, heart, brain and lung. In addition, this work estimate the damage depth in different types of tissues subjected to continuous wave CO2 laser. In this paper, three types of tissues have been used (muscle, lung and brain) which are subjected to different power level of CO2 laser intensity for 20 s. Some conclusions are obtained; as laser power increased the damage depth decreased; In addition, it is found that as water content increased the damage depth decreased, because of the water content of brain tissue is more than lung and muscle tissue, so that brain has damage depth less than muscle and lung tissues. The results of this research are of great interest in the medical field when using CO2 laser as cutting tool in surgery, which helps surgeons to know the damage that occurs when tissue is cut using CO2 laser.