One consequence of demographic change is a longer average remaining lifetime after retirement. Many people, however, remain able and willing to continue work after reaching the statutory retirement age. Given the predicted shortage of skilled workers in the future, post-retirement activities have the potential to contribute to both organisations and society. This article elaborates the prerequisites for productivity in retirement age and the changed nature of retirement at present. It also quantifies the extent to which activities are continued at retirement age. Paid employment still occurs beyond the applicable retirement age, whereby with increasing age, self-employed persons and assistant family members make up the lion's share of the statistics. An empirical study shows the concrete situation of active retirees and the prerequisites for post-retirement activities. At the explorative level, individual experiences of the transition into retirement, the reasons for and the framework of post-retirement activities, motivational factors in job design, and physical and intellectual demands before and after retirement are characterised. The qualitative data indicate that retirement entails changes towards more flexible structures in everyday life. Decisive reasons for taking up post-retirement activities are the desire to help, pass on knowledge or remain active; personal development and contact with others; and gaining appreciation and recognition. Flexible job design and freedom to make decisions constitute major elements in shaping postretirement working activities. Offering autonomy, skill variety, and task significance is important for the design of post-retirement activities. The paper closes with identifying relevant research fields and the concrete need to take action at individual, organisational, and societal levels. All in all, the transition from working life to retirement should be made flexible enough to do greater justice to the realities of life.