The aim was to assess in children with defaecation disorders, the accuracy of recalled information as provided by the child and/or parents compared to diary information and to evaluate its effect on diagnostic grouping. In this prospective study, recalled information, obtained initially by a telephone interview, was compared with recorded information provided by a 4-week diary. Recalled and recorded data were compared using Kappa indices. Subsequently, children were assigned to three diagnostic groups: constipation, solitary encopresis and a rest group. Based on these diagnoses, the first two groups were allocated for laxative treatment. Analysis of recalled and recorded data was performed in 46 children (5-14 years). Most defaecation parameters showed fair agreement, only limited agreement occurred for frequency of soiling episodes. Identical clinical groups using the two methods were obtained in 63% of the children. Particularly, the assessment of large amounts of stool and the number of soiling episodes were responsible for the shift in the diagnostic groups. A total of 83% children were correctly allocated for treatment using recalled data.