Within the science of rehabilitation and the medical research field there is a lack of an adequate instrument to assess work motivation. In order to be able to evaluate work-referred motivation structures with their strengths and weaknesses a multi-dimensional viewpoint was conceptualised on the basis of an interview study. Three new concepts were developed to which 12 scales with 202 items were assigned ("motivational self image" with six scales; "motivational intention of action" and "motivational goodness of fit" both with three scales). In a pilot study using a sample of vocational rehabilitants the major part of the concepts was identified using factor analysis. In certain areas modifications were made, so that 10 scales remained forming the basis for the development of a diagnostic instrument.