Aim: To study the legal, technical, and organisational issues of ensuring the confidentiality of personal and other medical data, in particular, in the context of the use of mobile medical applications (mHealth), various sets (bases) of medical data, in transplantology and the use of ART. Materials and Methods: The research materials comprised scholarly publications, legal acts, analytical reports from international organizations, and judicial practice relating to the problems of ensuring confidentiality and protection of personal and medical data in healthcare, particularly in transplantology and ART within the digital environment. The search for sources was conducted using international and national scientometric and legal databases, including PubMed, Scopus, and Web of Science, as well as official repositories of regulatory and legal acts of the European Union, the United States, and Ukraine. The chronological scope of the search covered the period from 2015 to 2025, which is justified by the rapid development of digital medicine, mobile health applications (mHealth), biobanks, and the growing incidence of cyber threats in the healthcare sector during this time frame. The search was conducted using the following keywords and their combinations in Ukrainian and English: confidentiality of medical data, personal data, digital medicine, mHealth, cybersecurity, protection of medical information, transplantology, and ART. Conclusions: Confidentiality is a fundamental component of the relationship between a doctor and a patient, which should be based on mutual trust, especially in the field of transplantology and the use of ART, which require medical professionals not only to clearly apply the norms of legislation in this area, but also to adhere to high moral and ethical standards of professional activity, taking into account, the need for permanent exchange of information between many participants in such special legal relations.