Medical rehabilitation in Germany has changed continuously since its inception following the Bismarck Legislation. This article describes its development up until the millennium and discusses quantitative and qualitative changes that followed. Central quantitative changes are demonstrated using the examples of rehabilitation utilization, spectrum of diseases, setting, and postacute rehabilitation. Important qualitative changes in medical rehabilitation pertain to the significance of research for the advancement of rehabilitation, the emphasis on work-related problems in rehabilitative concepts, patient orientation as a new paradigm, integration of rehabilitation into the health system, and prevention. The article ends with an outlook on future developments, such as the anticipated increase in rehabilitation need due to demographic changes and extended working life. Changes in the work environment lead to complex requirements for the development of rehabilitation. In view of increasingly scarce resources, continuous adaptation of rehabilitation concepts is mandatory to maintain health and earning capacity of the population.