This study was conducted to investigate knowledge and attitude factor related to hearing conservation and to evaluate the effect of knowledge and attitude about noise on hearing conservation behavior and hearing loss among workers exposed to noise. We investigated the questionnaires of knowledge and attitude about noise and hearing conservation behavior and hearing loss among 355 study subjects from March, 1998 to June, 1998. The results were as follows; We extracted following 5 factors from 26 questionnaire items of knowledge and attitude about noise; knowledge of noise and concern to the control noise (factor 1), general perceived susceptibility (factor 2), relative perceived susceptibility compared with colleagues(factor 3), concern to the hearing protective devices(factor 4), concern to the hearing and noise assessment (factor 5). Knowledge and attitude factors affecting the hearing conservation behavior were general perceived susceptibility in the case of wearing hearing protective devices and knowledge of noise and concern to the control noise in the case of suggestion for hearing conservation. But, in the case of intentional avoiding noise exposure, concern to the hearing protective devices was a significant factor with concern to the hearing and noise assessment. Knowledge and attitude factors affecting hearing loss in 1 kHz were relative perceived susceptibility compared with colleagues and concern to the hearing protective devices, and in 4 KHz were relative perceived susceptibility compared with colleagues and general perceived susceptibility.