Objectives: To describe the 'activities and participation' of children with cerebral palsy, as defined by the International Classification of Functioning, Disability and Health (ICF), using family-assessed instruments. Methods: A structured review of family assessed instruments appropriate for measuring children's activities and participation was undertaken to identify questionnaires for use in a postal survey. The survey involved a geographically-defined population of children with cerebral palsy between 6 and 12 years old, identified from the 4Child database in Oxford. Indices of children's 'activities and participation' were families' assessment of the Gross Motor Function (GMFCS) and Manual Ability (MACS) Classification Systems, the Activities Scale for Kids (ASK) and Lifestyle Assessment Questionnaire (LAQ-CP). To determine the reliability of families' assessments their classifications of the GMFCS and MACS were compared to ratings made professionals; the response frequencies and internal consistency of the ASK and LAQ-CP scales were also examined. Details of children's impairments and abilities were then used as explanatory variables in multiple regression analyses to identify the effect of disability on children's activities and participation. Results: Families of 129/314 (41%) of the children fully participated in the survey and 175/314 (56%) provided a classification using the GMFCS. These children did not differ from children who did not take part by age, gender or characteristics of their cerebral palsy and associated impairments. Although there was not always perfect agreement the families' classifications of children's movement and manual abilities using the GMFCS and MACS were highly reliable compared to those of health professionals (ICC>0.9). Analysis of the ASK and LAQ-CP showed these also to be reliable. Scores for the ASK and LAQ-CP were generally best predicted by children movement, manual and intellectual disability. Conclusions: Family assessment of children's movement and manual abilities using the GMFCS and MACS was highly reliable compared to health professionals. In concordance with similar studies that used professionally-assessed measures, children's activities and participation were most adversely affected by movement, manual and intellectual disabilities. Family assessment offers a highly reliable method for measuring activities and participation; however currently available instruments do not fully represent all the domains in the ICF.