BACKGROUND Patients with psychiatric or neurologic disease often suffer from neuropsychologic problems. The purpose of this study was to present a parental questionnaire (KOPKIJ) that assesses neuropsychologic problems in children and adolescents between 6 and 16 years of age. METHODS We tested theoretical analysis, standardization, and validation of the questionnaire in 352 healthy controls and 116 pediatric patients with epilepsy. RESULTS The objectivity of this standardized questionnaire can be considered high, and the reliability of the subscales is satisfying. Epileptic patients had higher scores than healthy controls, and the validation displayed reasonable connections with clinical factors and the results of neuropsychological evaluation. CONCLUSION The KOPKIJ allows an orientating appraisal clear picture of cognitive problems of children and adolescents at home and at school, simplifies anamnesis, and eases the planning of therapy strategies.