This study was conducted to investigate the prevalence rate of low back pain during past one year and its risk factors. The data were collected form 1,384 manafacturing factory workers from March 1, 1992 to August 30, 1992. The results obtained were as follows: 1. The one year prevalence rate of low back pain by manufacturing company was 38.4% in textile manufacturing, 35.2% in concrete reenforcement, 31.0% in cigarette and 26.1% in metal part(P<0.01). 2. In textile manufacturing, age groups with high prevalence rate of low back pain were 30's (36.8%) and 40's (36.4%) (P<0.05), and the one year prevalence rates of low back pain by marital state were 34.9% in married workers and 28.5% in unmarried(P=0.0511). 3. The one year prevelence rates of low back pain by job part are 35.0% in labor workers and 26.1% in clerical(P<0.05), and by work hour per day it was 34.9% in 9 or more and 28.9% in 8 or less (P<0.05). 4. The highest group of low back pain by work posture was 43.5% in 'lifting and transfering materials', and it by fitness of chair was 56.0% in uncomfortable one, and by height of working board was 33.6% in low working one. 5. In logistic regression analysis, significant determinants with low back pain were marital state (P<0.05), work hour per day(P<0.05), height of working board(P<0.01), and work posture(P<0.01).