The article presents the comprehensive Indicators of Reha Status (IRES) patient questionnaire that can be used for assessment and outcome measurement in rehabilitation. We explain why the ¿preventive-rehabilitative¿ orientation characteristic of the system of rehabilitation in Germany asks for particularly sensitive instruments as well as for inclusion of certain psychosocial variables. The results of validation studies are presented in some detail. In discussing possible applications of the questionnaire, we concentrate on its use for clinical practice (functional and psychosocial diagnostics, quality assessment). Finally, information is given on how to obtain questionnaires and the special computer programme for data entry and analysis.