Objective: Family-centered services are collections for children with special needs and their families. These services consider families as expert about children's needs. The essence of this approach is involvement of family in decision making, cooperation, and mutual communication (family and therapist), mutual respect, acceptance of family choice, family support, flexibility of service, and effort to empower families. These services have become a basic foundation of many early intervention programs and are especially useful in rehabilitation services. MPOC-20 is one of the questionnaires used to evaluate these services. This questionnaire consists 20 questions divided into 5 areas, the areas include the following: 1) enabling and partnership, 2) providing general information, 3) providing specific information about the child, 4) coordinated and comprehensive care for child and family, and 5) respectful and supportive care. This tool has been translated and validated in several countries and specifically in several diseases. In this study, the validity and reliability of this tool have been investigated. Materials & Methods: This study was a descriptive-analytical and in order to measure the validity and reliability of MPOC-20, content validity, correlation coefficient and reliability of the test-retest were done. To determine the content validity, 14 occupational therapists were asked and the result was calculated by measuring the content validity index and content validity Ratio. Then, an MPOC-20 questionnaire along with a form of demographic information and a consent form were given to 340 parents of children (children under 18 years and with different diagnosis) in clinics of Tehran. The articipants consisted of 142 girls patients (42%) and 198 boys (58%) randomly selected from public and private rehabilitation centers in different regions of Tehran. A large percentage of respondents were mothers (314 people were 92.4%). After 2 weeks, the questionnaire was again distributed among 30 of them, and the ICC coefficients were calculated. In order to determine the internal consistency, Cronbach's alpha was calculated. Results: The content validity index and content validity Ratio for all items were acceptable and no items were deleted. Cronbach's alpha was 0.81 which indicates a high correlation between items in the questionnaire. The highest Cronbach's alpha coefficient is related to the field of providing general information about the child (α=0.77). Also, in this section, the p-value was significant for all fields at the level of 0.001. In the reliability of the test-retest, the scores of the Intra-class correlation coefficient of all domains were higher than 0/6 which indicates a medium to good reliability of the questionnaire. Reliability in the field of supportive care had a high coefficient and good reliability. In other areas, the reliability was moderate. Conclusion: Considering the importance of evaluation in improvement of family-centered services provision, a strong tool is needed and MPOC-20 is well known in this regard. The results of this study showed that the Persian version of "MPOC-20" questionnaire has a good validity and reliability in children under the age of 18, and it can be used to assess family-centered services in both research studies and as clinical tool.