There is a need, among practitioners and researchers, for a feasible, user-friendly assessment tool that evaluates overall participation and guides intervention. This paper describes the process of construction and development of the Participation in Childhood Occupations Questionnaire (PICO-Q) and the establishment of its primary psychometric properties. The 22-item instrument measures the level, enjoyment, and frequency of performance for children's participation in daily occupations in a variety of environments. The questionnaire was completed by the mothers of 41 children between the ages of 6 and 10 years (24 children with and 17 children without sensory modulation disorder). Cronbach's alpha varied from. 86 to. 89, indicating internal consistency of items. Test-retest reliability varied from. 69 to. 86, indicating that the instrument provides a stable measurement over time. The PICO-Q was found to differentiate between children with and without participation restrictions. The PICO-Q shows initial reliability and validity and has both research and clinical application potential.