Introduction: Endometriosis can significantly impair the quality of life of those affected. Multimodal self-help measures are recommended but are often difficult to access. Smartphone apps have been shown to improve the quality of life for other conditions with chronic pain. The aim of this study was to examine the impact of the Endo-App (Endo Health GmbH, Chemnitz, Germany) on both disease-related quality of life and symptoms of endometriosis affecting it., Methods: In the present randomized, controlled pilot study, the impact of utilizing the Endo-App on the quality of life among a sample of 122 women affected by endometriosis is assessed. To measure the changes over a 12-week period, the study incorporates the validated Endometriosis Health Profile (EHP-5 and EHP-30) questionnaire from Oxford University, among other assessment tools., Results: The use of the Endo-App leads to significant changes in the following areas after 12 weeks compared to the control group: pain disability, pain self-efficacy, fatigue, depressive symptoms, and Endometriosis Health Profile scores. The EHP-5 score from T0 to T12 is reduced by -16.76 (p-value of the Mann-Whitney U test (p U ) = 0.008), and the EHP-30 score by -15.48 (p U = 0.004). The results remain significant in sensitivity analyses. The effect size of Cohen's d was in the medium range., Conclusion: In summary, the Endo-App improves both physical and psychological symptoms and the patient's self-efficacy. The Endo-App contributes to improving endometriosis care in Germany and enables women suffering from endometriosis to significantly increase their quality of life., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Ethics Committee of the State Chamber of Physicians of Saxony, Germany issued approval EK-BR-113/21-1. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: The Endo Health GmbH (formerly UG) received funding from the European Regional Development Fund (ERDF) from the state of Saxony, Germany. Financial relationships: Nadine Rohloff declare(s) employment and stock/stock options from Endo Health GmbH. CEO, Shareholder. Sebastian D Schäfer declare(s) non-financial support from Adboard AGE, Adboard EEL, Adboard SEF, WES Ambassador, Board AGEM. Nadine Rohloff declare(s) personal fees from DGE (German Nutrition Society). Reimbursement for lectures. Nicole R Heinze declare(s) employment from Medical School Hannover. Employment since 03/2024. Sebastian D Schäfer declare(s) Support for attending meetings and/or travel from Theramex. Teresa Götz, Sarah S Kortekamp, Nicole R Heinze, Charlotte Weber declare(s) employment from Endo Health GmbH. Sebastian D Schäfer declare(s) personal fees from Roche. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events. Sebastian D Schäfer declare(s) personal fees from Endo Health GmbH, Gedeon Richter GmbH, Baxter Medical GmbH, PlantTec Medical GmbH. Participation on a Data Safety Monitoring Board or Advisory Board, Consulting fees. Sebastian D Schäfer declare(s) personal fees from Eisai Pharma. Consulting fees . Intellectual property info: The Endo-App is a medical device and a registered trademark. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Rohloff et al.)