The purpose of the study was to examine the reliability and validity of the Canadian Occupational Performance Measure (COPM) in Taiwanese clients with psychiatric disorders. The COPM was translated into Mandarin and tested on 141 Taiwanese clients. The average age of the clients was 35.6 years; 94% were diagnosed with schizophrenia. The results of the study showed that the test retest reliability of the COPM was r = 0.842. The COPM identified occupational performance problems that included self-care (37%), productivity (25%), and leisure occupations (20%). Fifty percent of the therapists were receptive in adapting the client-centred approach and applying the COPM in their clinical practice. It was concluded that the COPM can be applied reliably to Taiwanese clients. Furthermore, the COPM was valuable in identifying information related to occupational performance that could not be identified elsewhere. Since 50% of the therapists felt reluctant about the appropriateness of the client-centred approach in their culture, it was important to examine the gap between clients' judgements and actual performance, as well as to evaluate the feasibility of the client-centred concept in clinical practice. Finally, the concept of the client-centred approach needs to be disseminated and communicated to the occupational therapy profession in order that the COPM can be adequately applied in mental health practice.