The aim was to evaluate whether the use of a client-centred instrument, the Canadian Occupational Performance Measure (COPM), affects the patients' perception of active participation in the rehabilitation process. The study included 155 patients in the experiment group and 55 in the control group, within geriatric, stroke, and home rehabilitation. The COPM was used in the experiment group. A structured interview was performed within 2-4 weeks after discharge with 88 patients in the experiment group and 30 patients in the control group. The results show significant differences between the groups. More patients in the experiment group perceived that treatment goals were identified, were able to recall the goals, felt that they were active participants in the goal formulation process, and perceived themselves better able to manage after completed rehabilitation compared with patients in the control group. The study indicates that the COPM improves client participation in the rehabilitation process.