It has been hypothesized that jobs that have both high psychological demands and low decision latitude ('job strain") can lead to musculoskeletal disorder. The objective of this study was to test whether job strain was correlated with the presence of work-related musculoskeletal disorder, especially myofascial pain syndrome (MPS). Information on demographic factors, confounders such as household load and taking care of children or not, and scores for decision latitude, job demand, and social support was obtained by self-administered questionnaire, which had been developed in Korean language, by adopting NIOSH instrument and Extended Karasek Model (16 items). All subjects were also examined by rehabilitation medicine specialists for musculoskeletal disorders. Subjects (n=370) could be categorized into 4 groups, these were, housewives(n=89), shipyard CAD workers(n=89), general female workers(n=79; nurses, insurance counselors, public officials, clerks, etc), and telephone directory assistance operators(n=113). Results from univariate analyses indicated that all demographic factors, all confounders, scores for decision latitude and social support were not associated with the risk of musculoskeletal disorder. However, score for job demand was higher in musculoskeletal disorder cases than others. In subgroup analysis, this association was convinced again, in telephone directory assistance operators. Job strain model showed that the group of telephone directory assistance operators was high-strain group, and OR of musculoskeletal disorder was 2.446 (95% C.I. : 1.174, 5.096), when comparing this with the low strain group. In conclusion, job strain is a risk factor for work-related musculoskeletal disorder.