Objective: The aim of this study was to determine the cumulative validity of experimental form in comparison with the Canadian Occupational Performance Measure) COPM( independently to identify occupational performance problems in the mothers of children with Cerebral Palsy (CP).

Materials & Methods: This study is an item refinement for experimental form, performed in two stages: firstly designing experimental form and testing reliability secondly its item refinement. Participants were 30 mothers of children with CP in first stage and 21 mothers of children with CP in second stage from different occupational therapy clinics in Tehran.

Results: In first stage, Spearman correlation coefficients showed that all the subscales had good test-retest reliability (r>0.7). There were observed significant difference in household management, quiet recreation, active recreation and socialization subscales of experimental form along COPM form compared COPM form alone in item refinement stage.

Conclusion: It seems that experimental form offers to detect more important occupational performance problems of mothers. Therefore, we recommended use of experimental form for knowing changes of mothers occupational of children with CP.