Purpose: The purpose of this study is to acknowledge the effects that have the strength exercise done only on the neck extensor, only on the thoracic extensor, and both the neck and the thoracic extensor on forward head posture(FHP) and cervical range of motion. Also is to discover which of the exercise is the most effective. Method: This experiment will be done by selecting 40 people who have 16cm or more FHP and they will be divided into four groups: three experimental groups and a control group. The first experimental group will do only the neck extensor strength exercise(NESE). The second experimental group will do only the thoracic extensorstrength exercise(TESE) and the third experimental group will do both the NESE and the TESE. The experimental groups will make a day three times each ten sets of extensor isometric strength exercise but the time will be increased from 4 to 6 and8 seconds until it will be done the ten sets. Then after four weeks, they will be compared which had the best results for the FHP and the cervical range of motion. Result: After the experiment, it was compared the experimental groups with the control group. Every experimental group had an improvement on their FHP and cervical range of motion. However, the only NESE and the only TESE did not have a significantly difference(p>.05). Only the group who did both the NESE and the TESE had a sign ificantly improvement compared to the control group. Conclusion: 1. The only NESE and the only TESE seem that had a positive effect on FHP and cervical range of motion. However, it cannot be conclude that it is effective. 2. When both the NESE and the TESE are done, it is showed statistically a significant difference(p<.05) on FHP and cervical range of motion. The refore, it would be note worthy if this exercise is used to improve the FHP and the cervical range of motion.