This paper aims at identifying major changes in and around work organizations, their effects upon job characteristics and the health and well-being of today's employees, and related research challenges. Increased internationalization and competition, increased utilization of information and communication technology, the changing workforce configuration, and flexibility and new organizational practices are considered. As work has changed from physical to mental in nature, job characteristics have changed significantly. Meanwhile work and family life have blended. New systems of work organization have become more prevalent, but they do not represent a radical change across the whole economy. New practices may have an adverse impact upon job characteristics, but their effects depend on their design, implementation, and management. Research recommendations include improved monitoring of changes in work organization and studies into their health and safety consequences, intervention studies, studies into the motivating potential of modern work practices, studies of marginalized workers and workers in less developed countries, and "mechanism studies".