Although self-concept is now recognised as a multidimensional construct, unidimensional measurement is still common practice for adults with mild intellectual disabilities. For this study, two groups of adults with intellectual disabilities were chosen from two institutions. One group were being prepared to move to community living (Movers) and the other group were staying at their residential service (Stayers). All of the participants had an IQ within the range of 56-75 for those with mild intellectual disability and within the range of 45- 56 for those with mild-moderate intellectual disability. Group 1 consisted of 25 adults who had a mean age of 47.9 years SD 9.7 years. Group 2 was a comparison group of 27 who were living in a different residential facility and had a mean age of 36.1 years SD of 8.1 years. Multidimensional self-concept was measured by Self Description Questionnaire-III (SDQ-III) and the Coopersmith Self-esteem Inventory (SEI) (Adult Version) Short Form was used to assess global self-esteem. The results indicated that the use of the SDQ-111 was valid for adults with mild intellectual disabilities as long as a modified individual testing format was used.