The use of job title as crude exposure measure in epidemiological studies is often inevitable when the available exposure data is scarce. In this study, an existing classification scheme of all job titles in the Netherlands into six categories of physical and mental work demands, constructed by expert judgement, was evaluated. Furthermore, a revision of this classification scheme for a research project on the relation between age, physical work demands, and musculoskeletal complaints was proposed and evaluated as well. For the evaluation, self-reported work demands, derived from questionnaire data of 38,921 employees and quantified by a scale of physical work demands and mental work demands, were used. Based on comparison of the mean scale scores of the several categories of work demands at group level, both classification schemes showed construct validity. Notwithstanding several limitations, the use of the presented classification schemes in epidemiological studies seems particularly challenging and rewarding when analysing data at group level from large and heterogeneous occupational populations. These kind of exploratory studies may generate new hypothesis on the basic patterns concerning work-related disorders, and can also be informative from a policy making perspective.