The Pain Disability Questionnaire (PDQ) is a new functional assessment instrument designed for evaluating chronic disabling musculoskeletal disorders. It is useful for assessing function/disability as affected by pain. This is the first study to assess the predictive validity of the PDQ in its relationship to 1-year post-treatment work- and health-related outcomes in a chronic disabling occupational musculoskeletal disorder (CDOMD) population. A prospective cohort of CDOMD patients (n=150) completed a prescribed functional restoration rehabilitation program, with PDQ and other psychosocial measures evaluated before and immediately after treatment. A structured telephonic interview for objective work- and health-related outcomes took place 1-year following treatment. Lower rates of work retention were associated with more severe pre-treatment PDQ scores. Higher post-treatment PDQ were associated with decreased return-to-work rates, decreased work retention and a greater percentage seeking health care from a new provider. In addition, PDQ scores were also associated with psychosocial measures such as depression and perceived pain intensity, as well as alternative measures of disability. Results demonstrated the ability of this simple and psychometrically-sound disability rating scale for systematic functional assessment in predicting treatment outcomes in patients with CDOMD. Results support the further use of the PDQ as a standard treatment outcomes measure in this area of musculoskeletal disorders.