A basic instrument is presented which enables essential parameters of rehabilitation patients' somatic, functional and psychosocial status to be brought out and data collected at a "middle level of detail" in a standardized manner, i.e. a patient questionnaire which can be used to complement medical assessment or, for example in follow-up, as a stand-alone tool. Development and testing of the instrument has been supported over the past three years by the LVA Württemberg pension insurance fund, both financially and conceptually. In the present article, questionnaire contents and structure are described, and validation findings reported, standardization on a representative sample of the resident population (n = 1848) is set out. The validation studies performed showed the instrument to be reliable, valid and sensitive, and meeting with good acceptance on the part of patients. Finally, a specifically designed computer programme is set out which facilitates questionnaire data input and basic analyses. Potential applications for the IRES questionnaire are for example seen in describing rehabilitation course and outcome, in documenting the effectiveness of rehabilitation measures (quality control), or in the framework of rehabilitation diagnosis, in particular relative to functional and psychosocial dimensions.