Acute health disorders with relevant impairments of functional health require the simultaneous acute-medical curative and rehabilitative treatment of the patient. The early initiation of rehabilitation during acute medical care is therefore not a new matter of concern. Nevertheless, up until now, excepting certain indications such as neurology and geriatrics, rehabilitation has often not been initiated at the earliest possible opportunity and not to a sufficient degree in acute settings. Legally, nothing has stood in the way of a combination of acute medicine and rehabilitation. As early as in the seventies, for instance, in the Reha-Angleichungsgesetz established the need for the early initiation of adequate rehabilitation. In the same law, hospitals were mentioned as one of the possible types of institution suitable for the implementation of rehabilitation. During the introduction of new Sozialgesetzbuch,Rehabilitation und Teilhabe behinderter Menschen" (SGB IX) it was nevertheless thought necessary to reiterate that early rehabilitation needs, beyond doubt, to be considered as a part of acute inpatient care. This article describes the legal basis for early rehabilitation in the acute hospital setting both before and after SGB IX came into effect.