Although some items from a questionnaire used to assess occupational and leisure activity in a cohort of male factory workers have reasonable validity, their reliability is unknown. In this study the reliability of this questionnaire was assessed in 54 middle-aged male factory employees by test-retest administration over a 4-6 week period. Kappa statistics for test-retest agreement for individual items on the questionnaire ranged between 0.24 and 0.66. Those items that demonstrated reasonable reliability and validity will subsequently be related to a range of disease endpoints in a prospective cohort study.