This study presented and evaluated an interview method for the analysis of tasks included in a work situation. What mental demands and possibilities do the work tasks give rise to? When was the work more or less automatic? When was use of active knowledge required? When were problem solving and planning needed? The study included an assessment of the interobserver reliability of the interviews with employees from 5 different careers: bus drivers (n = 10), home service workers (n = 32), carpenters (n = 11), farmers (n = 14), and teachers (n = 26). The extent to which this method can be reproduced in studies of different occupations is discussed. The interobserver reliability was good (.75-.82). There is support for the stability and usefulness of the interview for most types of work concerning the 3 categories of mental demands: routine, active knowledge, and problem solving/creativity.