The aim of this paper was to investigate the effectiveness of client-centred occupational therapy using the Canadian Occupational Performance Measure (COPM) and the Assessment of Motor and Process Skills (AMPS). Eight girls and 23 boys from Korea, with developmental disabilities and from 3 to 10 years of age participated in this study. Each child participated in 20 to 24 sessions of client-centred occupational therapy. Both the COPM and the AMPS change scores demonstrated statistically significant improvement (p < 0.01) in occupational performance. Sig-nificant correlations were found between COPM — Performance and AMPS — Motor skills (rs = 0.64, p < 0.05), and COPM — Satisfaction and AMPS — Process skills (rs = 0.62, p < 0.05) in a group positive towards client-centred occupational therapy. The COPM was a valuable tool in guiding and measuring the client-centred occu-pational therapy for children with developmental disabilities. The small sample size of 31 children limits the generalizability of the study's results. Future research needs to use a larger and more diverse sample of children to further validate the effective-ness of client-centred occupational therapy.