Background: The aim of this paper was to evaluate the reliability and validity of the Equity Perception Scale -- Intellectual Disability Services (EPS-IDS), a detailed measure of staff equity perceptions in services for people with intellectual disability (ID). The EPS-IDS contains 3 relationship indices that assess staff relationships with their employing organisation, their co-workers, and service users. Method: Postal questionnaires were used to collect quantitative data from a purposive sample of ID service staff. Results: The EPS-IDS was found to have good internal consistency reliability. The overall test-retest reliability of the measure, however, was found to be less satisfactory. With the exception of the co-worker relationship index, the EPS-IDS indices were found to have promising validity. Conclusions: The findings from the study suggest that the EPS-IDS shows some promise as a measure of the equity perceptions of ID service staff. Further refinements to the relationship indices, however, may be required.