Background: The experience of menopausal symptoms is common and an adequate patient-reported outcome measure is crucial in studies where women are treated for these symptoms. The aims of this study were to identify a patient-reported outcome measure for bothersome menopausal symptoms and, in the absence of an adequate tool, to develop a new measure with high content validity, and to validate it using modern psychometric methods. Methods: The literature was reviewed for existing questionnaires and checklists for bothersome menopausal symptoms. Relevant items were extracted and subsequently tested in group interviews, single interviews, and pilot tests. A patient-reported outcome measure was drafted and completed by 1504 women. Data was collected and psychometrically validated using item-response theory Rasch Models. Results: All questionnaires identified in the literature lacked content validity regarding bothersome menopausal symptoms and none were validated using item-response theory. Our content validation resulted in a draft measurement encompassing 122 items across eight domains. Following psychometrical validation, the final version of our patient-reported outcome measure, named the MenoScores Questionnaire, encompassed 51 items, including one single item, covering 11 scales. Conclusion: Menopausal symptoms are multidimensional with some symptoms unquestionably related to the menopausal transition. We identified four constructs of importance: hot flushes, day-and-night sweats, general sweating, and menopausal-specific sleeping problems. The MenoScores Questionnaire is condition-specific with high content validity and adequate psychometrical properties. It is designed to measure bothersome menopausal symptoms and all scales are developed and psychometrically validated using item-response theory Rasch Models.