The purpose of this study was to investigate the factors affecting hearing loss in adolescent's use of PCPs, and to give the basic data for adolescent's hearing conservation program development and prevention education against their hearing loss. This study was a descriptive research about three factors affecting hearing loss ; the knowledge and attitude about noise, the perception of hearing loss and the hearing threshold. The subjects of this study were 383 students in two general high schools and two vocational high schools in Teagu. They have been using PCPs but with no current or past ear disease. This study was carried out from Sep. 1, 2000 to Oct. 24, 2000. The instrument used for the knowledge and attitude about noise was a questionnaire developed by Rhee, Kyung Yong and Yi, Kwan Hyung(1996). The instrument used for the perception of hearing loss was a Smith Hearing Screening Questionnaire. A Belton Model 112 Audiometer, air-conduction hearing test instrument, was used for the hearing threshold. Data was analysed by a SPSS/Win 10.0 program with frequency, percentage, t-test, ANOVA and pearson correlation. The results of this study were as follows ; 1. The average of concern about hearing scored the highest 3.66+/-0.70. The average of perceived susceptibility scored 2.64+/-0.85 and the average of knowledge about noise scored 2.13+/-0.56. The average of total knowledge and attitude about noise scored 2.82+/-0.46. The average of discomfort of hearing loss(2.51+/-0.81) scored higher than that fear of hearing loss(1.35+/-0.53). The average of total perception of hearing loss scored 1.93+/-0.59. The hearing threshold of the subjects scored the highest at 500Hz(Lt. 23.21+/-6.62, Rt. 23.39 +/-7.02) and scored higher in order of 1000Hz, 2000Hz, 4000Hz and 8000Hz. 2. The knowledge and attitude about noise and the perception of hearing loss were both affected only by one important characteristic, which was general and vocational high schools. The knowledge and attitude about noise raked (t=5.258, p=0.000), and perception of hearing loss raked(t=2.241, p=0.026). However, several other important characteristics also impacted significantly on the knowledge and attitudes about noise. They included grade(t=1.987, p=0.048), father's education(F=2.745, p=0.043), marks(F=3.157, p=0.044), drinking(t=2.307, p=0.022) and smoking(t=2.587, p=0.010). The left hearing threshold differed significantly by sex at 1000Hz(t=5.175, p<0.001) and 8000Hz (t=3.334, p<0.01). According to general and vocational high schools(p<0.001), at 500Hz (t=-5.056), 1000Hz (t=-5.253), 2000Hz (t=-4.905), 4000Hz (t=-4.704) and 8000Hz (t=-5.204) significant differences were also shown. Marks were significant at 1000Hz (F=3.824, p<0.05) and drinking was found to be significant at 500Hz(t=2.203, p<0.05). The right hearing threshold differed significantly by sex at 1000Hz(t=5.557, p<0.001), 4000Hz(t=2.234, p<0.05) and 8000Hz (t=2.730, p<0.01). According to general and vocational high schools(p<0.001) at 500Hz (t=-4.730), 1000Hz(t=-6.271), 2000Hz (t=-4.573), 4000Hz(t=-3.554) and 8000Hz (t=-3.405) significant differences were also shown. Grades impacted at 500Hz(t=2.201, p<0.05) and 4000Hz(t=2.511, p<0.05), while marks were significant at 1000Hz(F=4.115, p<0.05) and drinking was significant at 500Hz(t=2.333, p<0.05). 3. The left hearing threshold in accordance with use of PCPs differed significantly at 2000Hz(F=2.996, p=0.031) according to volume level and at 8000Hz(F=2.197, p=0.022) according to durationxhours per day. The right hearing threshold differed significantly at 1000Hz(F=3.075, p=0.028) according to volume level and at 8000Hz(F=2.925, p=0.034) according to duration. 4. The knowledge and attitudes about noise showed a light positive correlation with the perception of hearing loss. A positive correlation was shown, as stated previously in all Hz, between the left hearing threshold and the right hearing threshold, especially the highest correlation at 2000Hz(r=0.761, p=0.000). This study has shown that the factors related to adolescent's use of PCPs are important as they impact significantly an adolescent's hearing. These results then indicate that in future, when designing a hearing conservation program and prevention education this data should be considered.