A model program for office reorganization and computerization has been developed and piloted in one of Sweden's public sector county administrative councils. The model emphasized extensive employee and user involvements in planning and designing the new office automation systems. Employees responsible for accounting and document registry tasks were the initial focus of activity. Questionnaires, structured interviews and physiological tests were administered on five separate occasions over an 18-month period to evaluate work efficiency and work environment, including psychological strain. The 42 female administrative assistants reported that their work required higher skill levels and was more interesting after the new computerized operations were in place. They also perceived their work as more demanding. Group average serum cortisol level increased by nearly 50%, indicating a substantial increase in occupational stress or mobilization. These findings suggest that office automation projects can increase perceived qualifications of work and lead to higher levels of job satisfaction while at the same time increasing work load with subsequent elevation of serum cortisol. These results can be characterized as “positive stress” according to a proposed model of technology in work and mental health. We attributed the group's more or less uniformly positive assessment of the new computerization project to extensive and early end user involvement.