The structure of a rehabilitation unit is an important feature of the quality of care. Adequate and qualitatively good structures provide the basis for appropriate therapy offers and treatment and eventually, a better health for rehabilitants. The quality of structures is generally recorded without any evaluation of the aspects in particular. The definition of standards is the basis for such an evaluation. The project presented is aimed at the definition of relevant structural standards for rehab units with inpatient treatment for musculoskeletal, cardiac, neurological, gastroenterological, oncological, pneumological and dermatological diseases. Here, the distinction between basal criteria which have to be fulfilled by every rehab unit with inpatient treatment and criteria important for a well-aimed assignment of patients with specific needs ("assignment criteria") should be made. Apart from the documentation of structural attributes, the structural quality of a rehab unit can be described individually as well as in comparison with other units. Relevant structural criteria were defined in expert meetings by means of a modified Delphi-technique with five inquiries. Overall, 199 "basal criteria" and "assignment criteria" were defined. All criteria can be assigned to the two domains general structural characteristics (general characteristics and equipment of rooms; medical/technical equipment; therapy, education, care; staff) and process-related structures (conceptual frames; internal quality management; internal communication and personnel development). The structural standards are applicable to units for musculoskeletal, cardiac, neurological, oncological, gastroenterological, dermatological and pneumological rehabilitation financed by the two main providers of rehabilitation, the statutory pension insurance scheme and the statutory health insurance scheme for all other five indications. The definition of structural standards agreed by experts in a formal consensus process, provides comprehensive and concrete requirements for German rehab units with inpatient medical rehabilitation. If the two main providers of rehabilitation both use the standards this can be regarded as a hallmark on the path to a unitary programme for quality management. The results enable units to analyse their weak points not just on an individual basis but allow also for a comparison between units, along with contributing to optimizing the structural quality of rehab units.