OBJECTIVES: Although psychometric properties of the Quality of Life InventoryTM (PedsQL) version 4.0 Generic Core Scales have been established in different pediatric populations, it has not been validated in patients with functional constipation (FC). The primary objective of the current study was to determine the reliability and validity of the Dutch translation of PedsQL in children with FC in The Netherlands. METHODS: The PedsQL was administered to 189 children and adolescents (aged 5-18 yrs) who met the Rome III diagnosis criteria for FC and 257 parents (of patients aged 2-18 yrs) recruited from 12 hospitals. Missing responses, internal consistency and reliability (Cronbach’s alpha), discriminant validity (t-test comparisons between children with FC and a separate sample of healthy children [from the literature]) and construct validity (Pearson correlation between a-priorihypothesized relationships between the PedsQL and disease-specific indicators, including the GI-module and the Defecation Disorder List), and inter-rater reliability between self- and parent-reports (Intraclass Correlations Coefficients, ICC) were assessed. RESULTS: The PedsQL showed minimal missing responses (5% child-, 0% parent-report) and achieved good to excellent internal consistency reliability for the Total Score (α 0.86 child, 0.88 parent), Physical Health Summary Score (α 0.75 child, 0.83 parent), and Psychosocial Health Summary Score (α 0.79 child, 0.85 parent). It also distinguished between healthy references and children with FC (d=0.28-0.57 child, 0.49-0.85 parent). The PedsQL was correlated to disease-specific reference measures (r varied from 0.23 to 0.57 child, 0.25 to 0.45 parent) consistent with the a-priori hypotheses. ICC’s between child and parent-reports ranged from 0.70 to 0.72. CONCLUSIONS: The results showed good initial measurement properties of the Dutch version of the PedsQL generic core scales in patients with FC. It could be considered as a valuable tool for measuring health related quality of life in Dutch speaking patients aged 2 to 18 years with FC.