The Hospital Adjustment Scale (HAS) is a 90-item behavior-rating scale designed for the assessment of the over-all level of psychological functioning, irrespective of psychiatric symptomatology, of hospitalized psychiatric patients. This paper reviews the research which has been done on and with the scale since its publication in 1953 and indicates the uses and limitations of the scale based on 15 yr. experience with it. It is concluded that adequate reliability and validity have been demonstrated to justify the scale's continued use as a measure of change in hospitalized psychiatric patients.