Whether rehabilitation services are initiated, applied for and (granted by German statutory pension funds) according to objectifyable need is uncertain as long as we lack a scientifically valid and operationally defined concept of "rehabilitation need". Traditionally three criteria are mentioned: neediness, ability, and prognosis. The text extends and specifies these criteria based on theoretical grounds, research evidence, and sociolegal considerations. It introduces a screening algorithm to objectify and assess individual rehabilitation needs focusing, as far as they are risk factors for participation restrictions, on a central disorder and its complications, risk and prognostic factors, comorbidities, motivational and other context factors. It proposes to relate more or less complex disturbances of functional health to more or less complex rehabilitation programmes and to indicate the typically complex ("holistic") in-patient rehabilitation only for equally complex health impairments and participation restrictions. Illustrative empirical data relate to three disorders, diabetes mellitus type 2, chronic disabling back pain, and chronic obstructive lung disease.