For assessing of impact Noise which is produced by pneumatic breaker, a study was performed in Hamadan during summer 1995.32 Kg pneumatic breakers of five services organizations were studied. Results show: background Noise, including Environmental and Air compressor Noise are in the range of 87 dBA-101 dBA and different in various type of cases. According to this study, SPL of breaker during operation are between 107 dBC and 111.5 dBC. Measurement of SPL in distance of 20m from sources are in the range of 83 dNA- 89.5 dBA.