The number of nursing home has increased largely in Japan since 1990. The Long-term Care Insurance in 2000 has accelerated the increase of nursing homes. The care giving and cooking in nursing homes have high risk factors of muscle-skeletal diseases (MSDs). However, the working conditions have not yet been improved. Thus, the incidence of low back pain and cervico-brachial disorder is very high among the care workers and cooks. Therefore, it is important to prevent the MSDs among the care workers and cooks. This study has been conducted to make a model of the participatory improvement focusing on low back pain in a nursing home for three years. As a result of the study, many improvements have been implemented and the incidence of low back pain has been reduced.