Background/Aims: The Leuven Postprandial Distress Scale (LPDS) is a validated patient reported outcome (PRO) measure for functional dyspepsia (FD)/postprandial distress syndrome (PDS) patients according to Rome III criteria. However, meal-related nausea or epigastric pain, part of PDS in Rome IV, were not addressed in this construct. Also, focus groups identified fatigue as a frequently reported complaint for which the European Medicines Agency requested further analysis. Our aim is to validate the LPDS in FD/PDS as defined by Rome IV criteria and to optimize the model by assessing the value of adding extra items to this questionnaire. Methods: The questionnaire was validated in 3 different Rome IV FD/PDS patient cohorts recruited for controlled clinical trials. Additional questions in the diary regarding symptom relationship to meal and fatigue were evaluated. Anchor scores were the patient assessment of gastrointestinal symptom severity index, Short-form Nepean dyspepsia index, the overall treatment evaluation and overall symptom severity questionnaires. Results: The LPDS Construct validity was confirmed for Rome IV-defined PDS. Psychometric analysis did not support inclusion of fatigue, nausea, meal-related or meal-unrelated, and meal-related epigastric pain, due to low loading or poor model fit. Conclusions The LPDS questionnaire showed good reliability and responsiveness, and can be confidently used as a validated tool in Rome IV PDS populations. Data did not support adding accessory symptoms to the construct, due to low loading or poor model fit.