Social skills are defining aspects of intellectual disability (ID). Additionally, their presence or absence can be a major impediment to independent living, and they correlate with other problems in the ID population, such as comorbid psychopathology. To date, little has been done to develop scales to measure these problems, particularly for adults. One exception has been the Matson Evaluation of Social Skills for the Severely Retarded ("MESSIER"). The scale has well established reliability, however many of its psychometric properties have yet to be explored. This study was designed to establish cutoff scores for the total score and factors and to explore the relationship of individual items to severity of social deficits. Participants are adults with severe or profound ID, assessed on the "MESSIER". Specific psychometrics for the test including cutoff scores are established. The implications of these data for theory, research, and practice are discussed. (Contains 3 tables.)