A study was conducted in order to determine back pain experience status of elementary. junior and senior high school teachers and the factors affecting their knowledge of back pain and physical therapy from April 2 through June 30, 1999 in major big cities and small and medium towns. Questionnaires were sent to 924 teachers and the collected daa were analyzed. The results summarized are as follows ; 1. $46.3\%$ of the respondents had experienced back pain, and $47.0\%$ of females, $62.0\%$ of the people over 50years old, $57.4\%$ of junior high school teachers, $47.5%$ of teachers of art and physical education, $46.9\%$ of married persons, $47.8\%$ of the people living in medium or small towns, and $58.6\%$ of the persons whose economic status was low han experienced back pains, $58.9\%$ of respondents who were not healthy, and $49.3\%$ of those who did not drink alcohol, $47.9\%$ of nonsmokers, and $49.1\%$ of those who slept on ondol had experienced back pains. $76.7\%$ of the respondents got health information on back pains from health professionals. 2. An average level of the respondents en physical therapy was $14.95pm8.32$ points out of 44 and it was 34 points when converted to 100. The knowledge levels of males,. elementary teachers, married persons, those teaching students far more than 20 hours a week, smokers, those who did not drink, those who exercised regularly, and those who had experienced back pains were higher than those in other groups. The knowledge level of those who had experienced back pain prevention education was $18.88pm8.88$ points and the difference between those with experience and those without experience was statistically significant. The depression level of those who got 40 pome on back pains, and physical therapy was higher than other group(p<0.001). 3, Depression levels of teachers on back pains and physical therapy related knowledge was higher in those with back pains than those without back pains(p<0.01). 4. The factors affecting experience of back pains were back pain related age, economic status, health status, smoking, style of kitchen, sown of information on back pain, and back pain prevention education. (p<0.001), 5. The factors affecting the knowledge on physical therapy were general knowledge levels on back pains, position when tilling, and moving heavy stuffs, driving position, sources of information on back pain prevention, type of bed, age, and health status, and the explanation power of those factors was $45.2\%$.