Introduction. Precise and adequate assessment of social functioning and disability is a subject of major interest and concern of the researchers. Until now, no instrument with confirmed psychometric properties was established as a supportive measure of disability in the framework of the rehabilitation process with the participation of the National Insurance Agency. A potentially useful instrument for this purpose is the Groningen Social Disabilities Schedule 11 (GSDSII). Aim. Aim of the study was the evaluation of usefulness of the Polish version of GSDSII as a social disabilities measure in the population of psychiatric inpatients. Method. 130 persons with a broad range of diagnoses (schizophrenia, mood disorders, anxiety disorders) were interviewed. For estimation of convergent validity, the following reference tools were selected: Global Assessment of Functioning (GAF), Social Assessment of Functioning scale (SOFAS), Global Assessment of Relational Functioning (GARF), World Health Organization Disability Assessment Schedule II (WHO-DASH). For criterion validity the Brief Psychiatric Rating Scale (BPRS) 24-item version was applied. Results. The sufficient and good validity indices were obtained for concurrent validity of GSDSII. There was also a significant interrelation between psychopathology assessed with BPRS and disability measured by GSDSII. Conclusions. Results allow for the supplication of the GSDSII in the research on psychosocial disability in Poland.