When developing a national biobank and repository for rare endometrial cancer subtypes, several ethical and practical considerations need to be taken into account. Ethically, ensuring patient privacy, confidentiality, and informed consent are paramount. Patients must understand how their samples will be used and stored, and their rights to withdraw consent should be respected. Additionally, issues of data security and protection against breaches must be addressed to maintain patient trust. Practically, establishing standardized protocols for sample collection, storage, and sharing is crucial to ensure the quality and integrity of the specimens. Collaborating with multiple institutions and researchers to contribute samples to the biobank requires clear guidelines for data sharing, authorship, and intellectual property rights. Moreover, funding and sustainability of the biobank are essential considerations to ensure its long-term viability and impact on translational research.