Background: This study analyzes the psychometric properties of the Portuguese version of the Quality of Life Questionnaire (QOL-Q; Quality of Life Questionnaire Manual--1993 Manual and 2004 Revision. 2004, IDS Publishing Company, Worthington, OH; Schalock & Keith 2004). Method: The analysis of the factorial structure was carried out on a sample of 304 adults with intellectual disabilities, through the use of confirmatory (CFA) and exploratory (EFA) factor analysis. The relationships of the QOL-Q with life satisfaction and self-concept measures were determined in groups composed of respectively 72 and 78 adults with intellectual disabilities. Results: Confirmatory factorial analysis indicated a poor adjustment of the original factor structure to the Portuguese data. EFA indicated the existence of four factors, which include 30 items, and that were also supported by CFA. The total score of the QOL-Q revealed a reduced correlation with life satisfaction, and a moderate correlation with the self-concept. Conclusions: The Portuguese version of the QOL-Q shows satisfactory psychometric properties, but also some limitations. (Contains 3 tables.)