Objectives. To examine the construct validity of the RSI in a contemporary cohort. Design. A cross-sectional investigation of 1,717 employed individuals who responded to the second stage of a study of occupational stress. Methods. Scores on the RSI are compared to smoking and drinking habits, social class, and two measures of health (number of days sick leave, and number of visits to a GP during the previous year). The RSI was compared to three measuring concepts related to stress: the 12-item General Health Questionnaire (GHQ-12), the Hospital, Anxiety and Depression Scale (HADS), and the Karasek Job Strain Questionnaire. Results. Higher levels of stress, as measured by the RSI, were associated with smoking a greater number of cigarettes, and, if the respondent drank alcohol, greater consumption W alcoholic drinks. High levels of stress were also associated with having taken more days sick leave, having made more frequent visits to a GP, and, somewhat unexpectedly with being a teetotaller, and with holding a non-manual occupation. Of the questionnaire measures, the strongest association was between the RSI and HADS anxiety subscale, consistent with an overlap between the concepts of stress and anxiety. Conclusions. This study supports the construct validity of the RSI in a sample of employed individuals.