Simple Summary Lymphedema is a common complication following gynecological cancer treatment, particularly affecting the lower limbs. However, self-reported data on lymphedema detection remain scarce. To address this gap, Yost developed the Lower Extremity Lymphedema Screening Questionnaire (LELSQ) specifically for women. The LELSQ is a straightforward and user-friendly tool designed for the early identification of lower extremity lymphedema (LEL). The validation of the questionnaire in Dutch was crucial for a larger trial called "The Gynolymph", since there were no validated questionnaires in Dutch for the detection of early LEL. This trial aims to enroll four hundred patients who will utilize the screening tool as part of a patient-reported assessment. By doing so, the trial seeks to detect the early development of lymphedema after cancer treatment. To ensure unbiased results, the study team translated and adapted the lymphedema questionnaire to Dutch. The cross-sectional survey conducted during this process demonstrated high internal consistency, test-retest reliability, and validity. Additionally, face and content validity were confirmed, allowing for the implementation of the questionnaire in the early detection of LEL among Dutch-speaking women.Abstract Background: Validated questionnaires of self-reported LEL are important in the assessment and diagnosis of LEL. The aim of this study was to validate and translate a Dutch version of the screening questionnaire, the LELSQ developed and validated by Yost et al. Methods: We tested the questionnaire on a group of healthy women and a group of patients diagnosed with LEL. The translation was carried out using the forward and backward method from English to Dutch. Statistical analyses: SPSS (IBM corp, Armonk, New York, NY, USA) version 28.0.1.0 (001) was used for statistical analysis in the process of validation. The internal consistency was assessed by determining Cronbach's alpha. The reliability was tested by test-retest reliability. The validity was determined ...