Factor analyses of health complaints in groups with different length of shiftwork exposure show that the structure of these complaints changes with increasing shift experience, indicating the emergence of a shift-specific pattern of health complaints. After about 15 years of shiftwork, complaints related to disturbances of circadian-controlled functions can be found in the first factor whereas other complaints have their dominant loadings on a separate factor, representing general, non-shift-specific impairments. The results indicate that in this way shift-specific components of health impairment can be separated from other non-shift related components.