The aim of this study was to report the preliminary validation results for the Pain Rehabilitation Expectations Scale (PRES). The PRES is a clinical tool developed to measure the expectations about rehabilitation treatment and outcome for people with back pain. Fifty people with chronic back pain were recruited from 11 physiotherapy outpatient clinics in Hong Kong for this study. Multitrait scaling analysis indicated that the three subscales of the PRES (working alliance, proxy efficacy, and motivation/expectation) were internally consistent, with Cronbach's alpha reliability coefficients ranging from 0.93 to 0.96. Proxy efficacy was found to be related to working alliance, and working alliance was positively related to client motivation and expectations. The preliminary psychometric analysis results suggested that the PRES could potentially be used to measure chronic pain patients' expectations about pain rehabilitation treatments. However, this study is based on a very small sample size; psychometric validation of the PRES with a larger sample of chronic pain patients to confirm the measurement structure of the PRES using confirmatory factor analysis is warranted.