Current questionnaires on defecation disorders are often brief and fail to include questions considering causative factors. Furthermore, adult and pediatric questionnaires differ, which makes it impossible to monitor defecation disorders during the transition from childhood to adulthood. With these points in mind, we developed the Groningen Defecation and Fecal Continence (DeFeC) questionnaire and its pediatric equivalent, the P-DeFeC. The aim of this paper is to introduce the questionnaires and to assess their feasibility, reproducibility and validity. Various Rome IV criteria and scoring tools for constipation and fecal incontinence were incorporated, resulting in nine categories. Feasibility and reproducibility were assessed by performing a test-retest survey in 100 adult participants. Concurrent validity was assessed in 27 patients and 18 healthy volunteers by comparing questionnaire-based diagnoses of constipation and fecal incontinence to final diagnoses based on anorectal function tests. There were no remarks on the understandability of any questions. The Cohen's kappa coefficient of all main questions ranged from 0.26 to 1.00, with an average of 0.57. All but one category showed moderate agreement or higher. The sensitivity of the questionnaire-based diagnosis of constipation was 75%; specificity was 100%. The sensitivity of the questionnaire-based diagnosis of fecal incontinence was 77%; specificity was 94%. Overall reproducibility of the Groningen DeFeC questionnaire is acceptable and its validity is good. This makes it a feasible screening tool for defecation disorders and, equally important, with these questionnaires defecation disorders can now be monitored during the transition from childhood to adulthood.