Most of the existing instruments for the assessment of social dysfunctioning of psychiatric patients are merely lists of precoded items, leaving little or no room for posing supplementary questions. In this article a new, semi-structured questionnaire--the Groningen Social Disabilities Schedule (GSDS)--is described, in which this shortcoming is met. The development of the GSDS is based on social role theory and on the existence of a hierarchy in social disabilities, demonstrated in an earlier World Health Organization study. Compatibility was sought with the International Classification of Impairments, Disabilities and Handicaps (ICIDH), a trial-classification of the World Health Organization, to be used in research on the consequences of illness. It is concluded that the inter-rater reliability of the GSDS is good. To a large extent the hierarchy proved to hold true for this instrument. Some implications for future research and for the ICIDH are discussed.