Out of the "Report on Workers" Casualties" presented by the employers in the entire nation in 1986 and 1988 to the Labor Standards Inspection Offices, 13,166 cases diagnosed as low back pain (5,820 cases in 1986 and 7,346 cases in 1988) were sampled and studied. This survey revealed that its incidence in men was about 4 times greater than that in women, being noted uniformely in all age groups except the 50 or older age group in men. As to types of industry, it was seen to be high in those working in the mining and cargo industries, as well as those working in the transport, traffic, forestry and agriculture, livestock, and fishing industries. As to the types of occupation, the incidence of low back pain was high in those working in transportation and construction. Onset was noted every month throughout the year, but a little less in December. It was pronounced at the beginning of the week, and seemed to peak immediately after starting the day's work, at 9 a.m. followed by 10 a.m. There was a trend toward accidental low back pain being caused frequently when one worked in an unnatural posture, especially in regular work when acting single-handed.