Providing appropriate support for people with profound intellectual and multiple disabilities (PIMD) is challenging, since valid and reliable instruments that can be used for assessment in persons with PIMD are scarce. Therefore, this study analyzes the usability and validity of an instrument developed for persons with PIMD, the Inventory of the personal Profile and Support (IPS). This instrument is part of a person-centered, goal-oriented, interdisciplinary intervention for persons with PIMD, which is called the “support program.” A first step in the support program is to draw up a personal profile, on which a long term goal for the person with PIMD can be based. When the IPS is used in combination with another instrument, the Behavior Assessment Scales (BAS), a support profile can be written. However, the IPS has not been studied on psychometric qualities yet. To look into the usability and content validity of the IPS, two questionnaires that were developed for this study were used for eight direct support persons of three care facilities. Although filling in the IPS is time-consuming and is therefore sometimes considered to be a burden, in general usability and content validity were rated as good. This study underlines the importance of using assessment instruments during different stages of support in a consistent, systematic way, using the input of all involved persons in support of the person with PIMD.